Mais uma vez, muito obrigado ao Marcelo Cazani (Marcazani) pela identificação deste pássaro.

Once more, thank you very much Marcelo Cazani (Marcazani) for the identification of this bird.

 

A text, in english, from Wikipedia, the free encyclopedia:

See at en.wikipedia.org/wiki/American_Kestrel

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American Kestrel

Adult male

Adult male

Conservation status

 

Least Concern (IUCN 3.1)

Scientific classification

Kingdom: Animalia

Phylum: Chordata

Class: Aves

Order: Falconiformes

Family: Falconidae

Genus: Falco

Species: F. sparverius

Binomial name

Falco sparverius

Linnaeus, 1758

Synonyms

 

Cerchneis sparverius

Tinnunculus sparverius

 

The American Kestrel (Falco sparverius) is a small falcon. This bird was (and sometimes still is) colloquially known in North America as the "Sparrow Hawk". This name is misleading because it implies a connection with the Eurasian Sparrowhawk Accipiter nisus, which is unrelated; the latter is an accipiter rather than a falcon. Though both are diurnal raptors, they are only distantly related.

American Kestrels are widely distributed across the Americas. Their breeding range extends from central and western Alaska across northern Canada to Nova Scotia, and south throughout North America, into central Mexico, the Baja, and the Caribbean. They are local breeders in Central America and are widely distributed throughout South America.

Most of the birds breeding in Canada and the northern United States migrate south in the winter, although some males stay as year-round residents. It is a very rare vagrant to western Europe.

The American Kestrel is the smallest falcon in North America—about the size of an American Robin. Like all raptors, the American Kestrel is sexually dimorphic, although there is some overlap within the species. The female ranges in length from 23 to 28 centimeters (9-11 inches) with a wingspan of 53–61 centimeters (21–24 inches) and weighs an average of 120 grams (4.2 ounces). The length of the male varies between 20–25 centimeters (8–10 inches) with a wingspan ranging from 51–56 centimeters (20–22 inches) and weighing an average of 111 grams (3.9 ounces). These subtle differences are often difficult to discern in the field.

The coloration of the feathers, however, greatly varies between the sexes. Males have blue-grey secondary feathers on their wings, while the undersides are white with black barring. The back is rufous in coloration, with barring on the lower half. The belly and flanks are white with black spotting. The tail is also rufous, except for the outer rectrix set, which is white with a black subterminal band.

The back of the female American Kestrel is rufous with dark brown barring. The wings exhibit similar coloration and patterning to the back. The undersides of the females are white with rufous streaking. The tail of the female is noticeably different from the male, being rufous in color with numerous narrow dark brown or black bars. Juveniles exhibit coloration patterns similar to the adults.

In both sexes, the head is white with a bluish-grey top. There are also two narrow, vertical black facial markings on each side of the head; one below the eyes and one on the rear portion of the auriculars. Two black spots (ocelli) can be found on each side of the white or orangish nape. The wings are moderately long, fairly narrow, and taper to a point. While perched, the wingtips are noticeably shorter than the tail tip.

The American Kestrel has three basic vocalizations - the "klee" or "killy", the "whine", and the "chitter." The "klee" or "killy" is usually delivered as a rapid series - "killy, killy, killy, killy" when the kestrel is upset or excited. It is used at the apex of the dive display, during fights with other kestrels, and after unsuccessful hunting attempts.

The "whine" may last as long as one to two minutes and may be single or treble. The more intense the situation, the more likely the "whine" will move toward the treble extreme. "Whines" are given during courtship feeding and copulation. The treble whine is heard from breeding females and fledged hungry young.

The "chitter" is the most frequent vocalization in male - female interactions. Its volume and duration depends upon the stress or excitement of the situation. It is associated with friendly approaches and bodily contact between the sexes during breeding season. Occasionally a "chitter" follows a "whine."

Calling occurs throughout the day. Nestlings at two weeks can produce all three vocalizations. Female kestrels tend to have slightly lower pitched and harsher voices than males.

This bird is apparently not a true kestrel. mtDNA cytochrome b sequence analysis (Groombridge et al. 2002) indicates a Late Miocene split[1] between the ancestors of the American Kestrel, and those of the Common Kestrel and its closest relatives. The color pattern with its large areas of brown is reminiscent of kestrels, but the coloration of the head - notably the black ear patch, which is not found in any of the true kestrels - and the male's extensively gray wings are suggestive of a closer relationship with the hobbies, an informal grouping of falcons of usually average size.

Species such as the Merlin and the Aplomado Falcon are proposed as possible close relatives. Indeed, the Merlin is a highly polymorphic bird and although its grey tail and back are distinctive, certain morphs are the only birds that might conceivably be confused with American Kestrels. Conclusive evidence is lacking, and what can be said at present judging from the fairly noninclusive DNA sequence studies[2] is that the general relationships of the present species seem to lie with a number of rather basal "hobby" lineages, such as the Merlin and Aplomado Falcon mentioned already, or the Red-footed and Amur Falcons - or even the Peregrine Falcon lineage with its large species.

The American Kestrel is not very closely related to any of these groups, although it might be closer to the Aplomado Falcon (and its presumed close relatives, the Bat and Orange-breasted Falcons) than to any other living species (Wink et al. 1998) - an association that is also better supported by biogeography than a close relationship with the exclusively Old World true kestrels. It is nonetheless highly distinct in morphology from any of these and, interestingly, has a syrinx similar to the Peregrine and the hierofalcons[3].

In conclusion, until better evidence is available, it is best considered part of a radiation of falcon lineages that diversified around the North Atlantic at the end of the Miocene. Though several fossils of small falcons arte known from North America at roughly the correct time, the earliest testimony of the American Kestrel lineage is Pleistocene remains of the living species (Brodkorb 1964).

American Kestrels are found in a variety of habitats including parks, suburbs, open fields, forest edges and openings, alpine zones, grasslands, marshes, open areas on mountainsides, prairies, plains, deserts with giant cacti, and freeway and highway corridors.

In addition to requiring open space for hunting, American Kestrels seem to need perches for hunting from, cavities for nesting (either natural or man-made), and a sufficient food supply.

The American Kestrel is the only North American falcon to habitually hover with rapid wing beats, keeping its head motionless while scanning the ground for prey. The kestrel commonly perches along fences and powerlines. It glides with flat wings and wingtips curved upward. It occasionally soars in circles with its tail spread and its wings flat.

This falcon species is not long-lived. The oldest banded wild bird was 11 years and seven months old while a captive lived 17 years. A mortality rate average of 57 percent was found. First year mortality rates have declined since 1945 with a decrease in shooting. Major causes of death include collision with traffic, illegal shooting, and predation by other raptors, including the Red-tailed Hawk, Northern Goshawk, Cooper's Hawk, Peregrine Falcon, Barn Owl, and Great Horned Owl.

In summer, kestrels feed largely on grasshoppers, dragonflies, lizards, mice, and voles. They will also eat other small birds. Wintering birds feed primarily on rodents and birds. The birds characteristically hunt along roadsides from telephone wires, fence posts, trees or other convenient perches when not flying in search of food. When they are flying and looking for food they frequently hover with rapid wingbeats.

Because it feeds on both insects and vertebrates, the American Kestrel maintains fairly high population densities. It has a small breeding home range, from 1.75 square miles (4.5 km²) to 2 square miles (5.2 km²). Territory size has been estimated at 269 acres (1.1 km²) to 321 acres (1.3 km²) with much larger wintering home ranges.

Several hunting techniques are used by the American Kestrel. It will hover over one spot—when prey is sighted the kestrel will partly fold its wings and drop lower once or several times before striking. When the prey disappears the falcon will glide in a semicircle before turning back into the wind to hover again. It will also soar in circles, or figure eights, using the same stooping tactics as when hovering.

The kestrel commonly hunts from elevated perch sites, waiting for prey to move on the ground. The kestrel bobs its head and pumps its tail just before attacking.

Other prey capture techniques include direct pursuit, landing and flushing prey from the ground (especially for grasshoppers)and then taking them in flight, capturing flying insects from an elevated perch, and nest robbing including the burrows of Bank Swallows and the nests of Cliff Swallows. It is also an occasional bat catcher, taking bats from their tree roosts, or striking bats in flight from above or as the bats leave or enter caves. The kestrel will kill and cache food items.

The American Kestrel occasionally robs others of the same species. It has also been known to rob a shrike of its prey. Kestrels sometimes harass other hawks, and even Golden Eagles, in flight.

American Kestrels form pairs in which the bond is strong, tending toward permanence. Returning migrants commonly re-establish territories held the previous year. In one study[citation needed], a pair nested in the same tree for six consecutive years. Nesting occurs from late spring to late summer in North America, with incubation underway by the end of May[4]; in tropical South America the birds breed roughly from June onwards through to September or so[5].

Courtship begins shortly after the male establishes a territory. In early courtship, he may give the "dive display", a series of climbs and dives 33 to 66 feet (10 to 20 m) with 3-5 "klee" notes given near the peak of each climb. He may present the female with food during courtship feeding. He may entice her to the nest site by calling. He may "flutter-glide" toward her with quick and shallow wing beats while carrying food and she may also beg for food by flutter-gliding. The female initiates copulation by bowing with her tail in line with her body or slightly raised.

A cavity nester, American Kestrels will use holes in trees, rock cavities and crevices in cliffs, artificial nest boxes, or small spaces in buildings. The number of suitable breeding cavities limits this species' breeding density. The American Kestrel has adapted well to nest boxes. In one program, nest boxes were fixed to the backs of signs along a freeway thus allowing kestrels to breed in areas formerly devoid of nest sites. Pairs nesting in boxes on poles have much higher nesting success than pairs using boxes on trees. No nest is built inside. In nest boxes sawdust and wood shavings may be a suitable substrate for the eggs. Males and females defend the nest against intruders, with the male maintaining a small core territory and the female defending the nest cavity directly rather the surroundings[5].

Both sexes take turns incubating their eggs, a very rare situation among North American birds of prey where the female usually incubates exclusively. Correspondingly, both sexes develop bare oval patches on each side of their breasts where the warm bare skin can contact the eggs for warming. Eggs hatch 29 to 31 days after being laid.[6] There are from three to seven eggs laid, but four to six are average.[6] The eggs are typically short elliptical in shape, and are white or pinkish-white with an even covering of fine spots and flecks of brown shades, occasionally concentrating as a ring or a cap. They will renest if the first nest fails and have been reported to raise 2 broods per year in some of the southern states.

The young grow very quickly, becoming noisy between day 11 and 14 and assuming adult weight in about 2.5 weeks. The young fledge in 30 to 31 days.[7] [6]Early fledgling behavior varies. Broods typically stay together for a week or two. Some broods remain close to the nest area for a week or two while others travel throughout the parents' home range. Generally, young do not disperse more than 0.6 miles (one km) away from the nest area until two to four weeks old. Young disperse as hunting skills develop. Occasionally groups of older juveniles from various broods join together into flocks.

The American Kestrel can be double-brooded, particularly in the southern United States, in areas of abundant small mammals. Replacement clutches can be laid.

 

Um texto em português:

Falcão-americano ou quiriquiri (Falco sparverius) é um pequeno falcão (23-27 cm de comprimento e 85-140 g de peso). Tem uma ampla área de distribuição: desde o Alasca e Norte do Canadá até à ponta Sul da América do Sul (Terra do Fogo). Tem asas azul acizentadas. O dorso é avermelhado pontuado de preto. A cauda também é avermelhada possuindo uma larga lista preta. Na face possui 2 listas verticais que começam junto aos olhos e seguem para baixo. É um predador de pequeno tamanho, alimentando-se de insetos e microvertrebrados como roedores e pequenos pássaros; ocasionalmente caça morcegos.

Falcão é o nome genérico dado a várias aves da família Falconidae, mais estritamente aos animais classificados dentro do género Falco. O que diferencia os falcões das demais aves de rapina é o fato de terem evoluído no sentido de uma especialização no voo em velocidade (em oposição ao voo planado das águias e abutres e ao voo acrobático dos gaviões), facilitado pelas asas ponteagudas e finas, favorecendo a caça em espaços abertos – daí o fato dos falcões não serem aves de ambientes florestais, preferindo montanhas e penhascos, pradarias, estepes e desertos. Os falcões podem ser identificados, aliás, pelo fato de não planarem em correntes termais, como outras aves de rapina. O falcão-peregrino, especializado na caça de aves médias e grandes em voo, pode atingir 300 km/h em voo picado e é o animal mais rápido da terra. Diferentemente das águias e gaviões, que matam suas presas com os pés, os falcões utilizam as garras apenas para apreenderem a presa, matando-a depois com o bico por desconjuntamento das vértebras, para o que possuem um rebordo em forma de dente na mandíbula superior.

Na Idade Média, os falcões eram apreciados como animais de caça acessíveis apenas à elite.

The viviparous lizard, or common lizard, (Zootoca vivipara, formerly Lacerta vivipara) is a Eurasian lizard. It lives farther north than any other species of non-marine reptile, and is named for the fact that it is viviparous, meaning it gives birth to live young (although they will sometimes lay eggs normally). Both "Zootoca" and "vivipara" mean "live birth", in (Latinized) Greek and Latin respectively. It was called Lacerta vivipara until the genus Lacerta was split into nine genera in 2007 by Arnold, Arribas & Carranza.

 

Male and female Zootoca vivipara are equally likely to contract blood parasites. Additionally, larger males have been shown to reproduce more times in a given reproductive season than smaller ones.

 

The lizard is also unique as it is exclusively carnivorous, eating only flies, spiders, and insects. Studies show that the more carnivorous an individual is (the more insects they eat), the less diverse the population of parasitic helminths that infest the lizards.

 

Zootoca vivipara lives in very cold climates, yet participates in normal thermoregulation instead of thermoconformity. They have the largest range of all terrestrial lizards which even include subarctic regions. It is able to survive these harsh climates as individuals will freeze in especially cold seasons and thaw two months later. They also live closer to geological phenomena that provide a warmer environment for them.

 

Description

Zootoca vivipara is a small lizard, with an average length between 50 and 70 mm (2.0–2.8 in) and an average mass of 2 to 5 g (0.071–0.176 oz). They exhibit no particular colour, but can be brown, red, grey, green, or black. The species exhibits some sexual dimorphisms. Female Z. vivipara undergo colour polymorphism more commonly than males. A female lizard's display differs in ventral colouration, ranging from pale yellow to bright orange and a mixed colouration. There have been many hypotheses for the genetic cause of this polymorphic colouration. These hypothesis test for colouration due to thermoregulation, predator avoidance, and social cues, specifically sexual reproduction. Through an experiment conducted by Vercken et al., colour polymorphism in viviparous lizard is caused by social cues, rather than the other hypotheses. More specifically, the ventral colouration that is seen in female lizards is associated with patterns of sexual reproduction and sex allocation.

 

The underside of the male is typically more colourful and bright, with yellow, orange, green, and blue, and the male typically has spots along its back. On the other hand, females typically have darker stripes down their backs and sides. Additionally, males have been found to have larger heads than their female counterparts, and this trait appears to be sexually selected for. Males with larger heads are more likely to be successful in mating and male-male interactions than smaller-headed Z. vivipara. Larger males also have been shown to reproduce more frequently during one mating season compared to smaller males. Characteristic behaviors of the species includes tongue flicking in the presence of a predator and female-female aggression that seems to be mediated by the colour of their side stripe.

 

Habitat and distribution

Z. vivipara is terrestrial, so they spend most of their time on the ground, though they do occasionally visit sites of higher elevation. The lizard thermoregulates by basking in the sun for much of the time. In colder weather, they have been known to hibernate to maintain proper body temperatures. They hibernate between October and March.[11] Their typical habitats include heathland, moorland, woodland and grassland.

 

The viviparous lizard is native to much of northern Eurasia. In Europe, it is mainly found north of the Alps and the Carpathians, including the British Isles but not Iceland, as well as in parts of northern Iberia and the Balkans; In Asia it is mostly found in Russia, excluding northern Siberia, and in northern Kazakhstan, Mongolia, China, and Japan.[citation needed] Z. vivipara has the largest distribution of any species of lizard in the world.

 

Home range

The size of the home range of the lizard ranges from 539 m2 to 1692 m2, with males generally having larger home ranges. The size of an individual lizard's home range is also dependent on population density and the presence of prey.

 

Ecology

Diet

Unlike many other lizards, Z. vivipara is exclusively carnivorous. Their diet consists of flies, spiders, and various other insects, including hemipterans (such as cicadas), moth larvae, and mealworms. The species is a predator, so it actively hunts down all of its prey. One study found that when controlled for body size, females consumed more food than males. Feeding rates also increased with increased sunshine.

 

Predation

Birds are common predators of Z. vivipara. Male-biased predation of Z. vivipara by the great grey shrike (L. excubitor) has been studied, finding that adult males, over adult females and juveniles, were preferentially predated on. This bias may be due to increased activity of adult males during the reproductive season.

 

Predators of this species include birds of prey, crows, snakes, shrikes, hedgehogs, shrews, foxes, and domestic cats.

 

Diseases and parasites

Z. vivpara can be infested by helminths, a small parasitic worm. The species diversity of parasites is affected by the diet of the individual lizard and the number of parasites on a host is affected by the host's size. Results of a study shows that the more carnivorous an individual is, the less diverse its parasite population. Additionally, larger lizards had a greater number of parasites on them.

 

Z. vivipara is also infected by blood parasites. In a study investigating the prevalence of blood parasites in Z. vivipara and L. agilis, Z. vivipara was found to be parasitized with an incidence rate of 39.8%, while L. agilis was parasitized with an incidence rate of 22.3%. This same study shows that there was not a significant difference between the parasitization of male and female Z. vivipara.

 

Reproduction and life history

The viviparous lizard is named as such because it is viviparous. This refers to its ability to give birth to live young, although the lizards are also able to lay eggs. The origin of this characteristic is under debate. Some scientists argue that viviparity evolved from oviparity, or the laying of eggs, only once. Proponents of this theory also argue that if this is the case, it is possible, though rare, for species to transition back to oviparity. Research from Yann Surget-Groba suggests that there have in fact been multiple events of the evolution of viviparity from oviparity across different clades of the viviparous lizard. They also argue that a reversion to oviparity is not as rare as once believed, but has occurred 2 to 3 times in the history of the species.

 

The range of viviparous populations of Z. vivipara extends from France to Russia. Oviparous populations are only found in northern Spain and the southwest of France. Some research in the Italian alps has suggested that distinct populations of oviparous and viviparous Z. vivipara should be considered separate species. Cornetti et al. (2015) identified that viviparous and oviparous subpopulations in contact with each other in the Italian alps are reproductively isolated. Hybridization between viviparous and oviparous individuals of Z. vivipara leads to embryonic malformations in the laboratory. However, these crosses do produce a "hybridized" generation of offspring, with females retaining embryos for much longer in utero than oviparous females, with embryos surrounded by thin, translucent shells.

 

Fertilization

Z. vivipara juveniles reach sexual maturity during their second year of their life. A study that explored the presence of male sex cells in reproducing males found that for the two weeks following the end of hibernation, males are infertile, and therefore incapable of reproducing. The same study also found that larger males produce more sperm during the reproductive season and have fewer left over at the end of the reproductive season than their smaller counterparts. This suggests that the larger a male is, the more reproductive events they participate in.

 

Brood size

Research also suggests that in exclusively oviparous populations of Z. vivipara, altitude influences the number of clutches laid in a reproductive season as well as when reproduction begins. Generally, lizards living at higher altitudes have been found to begin reproduction later and lay fewer clutches (often 1) in a given reproductive season.

 

Life span

Z. vivipara typically lives for 5 to 6 years.

 

Mate searching behavior

Head size is a sexually dimorphic trait, with males having larger heads than females. The average head width and length of the males measured were found to be 5.6 and 10.5 mm (0.22 and 0.41 in), respectively. The average head width and length of the females measured were found to be 5.3 and 9.7 mm (0.21 and 0.38 in), respectively. During the first state of courtship in Z. vivipara, called "Capture", the male uses its mouth and jaw to capture the female and initiate copulation.[6] The results of this study demonstrated that males with larger head sizes (both length and width) were more successful in mating than those with smaller heads, suggesting that head size undergoes sexual selection.

 

Male-male interaction

Head size has also been shown to be a predictor of success in male-male interactions. The head is used as a weapon in male-male interactions, and a larger head is typically more effective, leading to greater success during male-male aggressive encounters. This aggression and interaction is centered around available mates, so males with smaller heads have significantly less access to females for reproduction.

 

Thermoregulation

This lizard has an exceptionally large range that includes subarctic geography. As a result, thermoregulation is necessary for the thermal homeostasis of the species. Typically, in temperature extremes, a species will adopt the behavioral strategy of thermoconformity, where they do not actively thermoregulate, but adapt to survive in the harsh temperature. This occurs because the cost of thermoregulating in such an extreme environment becomes too high and begins to outweigh the benefits. Despite this, Z. vivipara still employs the strategy of thermoregulation, like basking. Thermoregulation is important in Z. vivipara as it allows for proper locomotive performance, escape behavior, and other key behaviors for survival. The ability of Z. vivipara to thermoregulate in such harsh environments has been attributed to two primary reasons. The first is that Z. vivipara has remarkable behaviors to combat the cold, and there are geological phenomena in their distribution that maintains their habitats at a temperature that the species can survive in. One of the specific behaviors used to combat the extreme cold is a "supercooled" state. Z. vivipara remains in this state through the winter until temperatures dropped below −3 °C (27 °F). After that, individuals completely froze until they were thawed by warmer weather later in the year, often 2 months later. Despite very cold air in the subarctic habitats of these lizards, the soil-heating effects of unfrozen groundwater has been observed regulating the temperature of their soil habitats. They find warm microhabitats that do not drop below the freezing point of their body fluids. These lizards have exceptional hardiness to the cold, which allows them to hibernate in upper soil layers in temperatures as low as −10 °C (14 °F). This cold hardiness along with the favorable hydrogeological conditions of groundwater-warmed soil habitats allows for the wide distribution of lizards throughout the palearctic.

 

The colour polymorphism of female Z. vivipara has not been thoroughly studied in past years, regardless of the extensive research done on the species itself. Females exhibit three types of body colouration within a population: yellow, orange, and mixture of the two. These discrete traits are inherited maternally and exist throughout the individual's lifetime. The organism's colour morphs are determined by their genotype as well as their environment.

 

The frequency of multiple morphs occurring in a population varies with the level of population density and frequency-dependent environments. These factors cause the lizards to vary in terms of their fitness (clutch size, sex ratio, hatching success). In lower density populations, colour polymorphism is more prevalent. This is because viviparous lizards thrive in environments where intraspecific competition is low. Increased competition among individuals results in lower survival rates of lizards. Additionally, female lizards disperse through habitats based on the frequency of colour types that are already present in the population. Their reproductive abilities vary according to this frequency-dependent environment. The number of offspring that they produce correlates with the colour morph: yellow females produce the fewest offspring, while orange females produce more than yellow, but fewer than mixed females, which produce the most offspring. The amount of offspring produced varies in regards to colour frequencies in the population; for example, if yellow females have higher density within the population, the clutch size for orange lizards is usually lower.

 

Orange females are more sensitive to intraspecific and colour-specific competition. They have smaller clutch sizes when the density of the population is high, or when the number of yellow females in the population is high. This could be due to their need to conserve energy for survival and reproductive events.[9] Their colour morph remains in the population due to the trade-off between the size of offspring and the clutch size. Offspring born in smaller clutches are often larger and thus have a higher survival likelihood. Natural selection will favor individuals with larger size because of their advantage in physical competition with others. Yellow females have larger clutch sizes early in their life, but their hatch success decreases as the female ages. Their reproductive viability decreases, resulting in fewer offspring throughout their lifetime. Yellow morphs remain in the population due to their large clutch size, which causes an increased frequency of those females. Selection favors the yellow morph because of the ability to produce large clutch sizes, which increases the female's fitness. In mixed-coloured females, reproductive success is less sensitive to competition and frequency-dependent environments. Since these lizards show a mixture of yellow and orange colouration, they adopt benefits from both of the morphs. As a result, they can maintain high reproductive success and hatching success with large clutch sizes. Their colour morph remains in the population due to its high fitness, which selection will favor.

 

All three colours have evolutionary advantages in different ways. While yellow females have higher fitness due to their large clutch sizes, orange females enjoy high fitness due to their large body size and increased competitive advantages. Mixed females exhibit both of these advantages.

Common Name Greater Mormon

Papilio memnon

Lepidoptera: Papilionidae

Range: N. india through Burma to China, south to Malaysia, Java

Ours arrive from: Malaysia

 

Food: Plants in the citrus family

 

Notes: These butterflies are polymorphic, meaning that they occur in many forms. Males and females differ in color patterns, and also some females of this typically tailless swallowtail develop with a tail on each wing. Females mimic the unpalatable roses (Pachliopta spp.).

    

Tenerife

Icod de los Vinos

Butterfly garden

 

www.mariposario.com/en/

 

Papilio memnon, the great Mormon, is a large butterfly native to southern Asia that belongs to the swallowtail family. It is widely distributed and has thirteen subspecies. The female is polymorphic and with mimetic forms.

en.wikipedia.org/wiki/Papilio_memnon

Lucky to meet up with this Rare Winter Visitor on it way back to North, view from another angle.

 

Asian Paradise-flycatcher (Terpsiphone paradisi) "Incei" subspecies

 

(T. p. incei (Gould, 1852) breeds in eastern, northeastern and central China, in the Russian Far East and in the north of Korea; populations occurring in Southeast Asia are non-breeding.)

  

The Asian paradise flycatcher (Terpsiphone paradisi) is a medium-sized passerine bird native to Asia. Males have elongated central tail feathers, and in some populations a black and rufous plumage while others have white plumage. Females are short-tailed with rufous wings and a black head. They feed on insects, which they capture in the air often below a densely canopied tree.

 

With an extremely large range and a large population that appears to be stable, they have been evaluated as Least Concern by IUCN since 2004.

 

In his first description of 1758, Carl von Linné nominated the species Corvus paradisi. Paradise-flycatchers used to be classified with the Old World flycatcher family Muscicapidae, but are now placed in the family Monarchidae together with monarch flycatchers.

  

Characteristics

 

Adult Asian paradise flycatchers are 19–22 cm (7.5–8.7 in) long. Their heads are glossy black with a black crown and crest, their black bill round and sturdy, their eyes black. Female are rufous on the back with a greyish throat and underparts. Their wings are 86–92 mm (3.4–3.6 in) long. Young males look very much like females but have a black throat and blue-ringed eyes. As adults they develop up to 24 cm (9.4 in) long tail feathers with two central tail feathers growing up to 30 cm (12 in) long drooping streamers.

Young males are rufous and have short tails. They acquire long tails in their second or third year. Adult males are either predominantly bright rufous above or predominantly white. Some specimens show some degree of intermediacy between rufous and white. Long-tailed rufous birds are generally devoid of shaft streaks on the wing and tail feathers, while in white birds the shaft streaks, and sometimes the edges of the wing and tail feathers are black.

 

In the early 1960s, 680 long-tailed males were examined that are contained in collections of the British Museum of Natural History, Chicago Natural History Museum, Peabody Museum, Carnegie Museum, American Museum of Natural History, United States National Museum and Royal Ontario Museum. The specimens came from almost the entire range of the species, though some areas were poorly represented. The relative frequency of the rufous and white plumage types varies geographically. Rufous birds are rare in the extreme southeastern part of the species' range. Throughout the Indian area and, to a lesser extent, in China, asymmetrically patterned intermediates occur. Intermediates are rare or absent throughout the rest of the range of the species. In general, long-tailed males are:

 

- predominantly rufous with some white in wings and tail — collected in Turkestan, Kashmir, northern India, Punjab, Maharashtra, Sikkim and in Sri Lanka;

 

- predominantly rufous with some white in wings — collected in Iran, Afghanistan, Baluchistan, Punjab, Kashmir, northern and central India, Rajasthan, Maharashtra, Bihar, Nepal;

 

- predominantly rufous with some white in tail — collected in Punjab, northern and central India, Kolkata, Sri Lanka and in the Upper Yangtse Valley in China;

 

- predominantly white with some rufous in tail and wings — collected in Kashmir, Maharashtra, Sichuan and North China;

 

- predominantly white with some rufous in tail — collected in Maharashtra and Fuzhou, China;

 

- predominantly white with back partly rufous — collected in Punjab and Chennai;

 

- predominantly white with wings and tail irregularly blotched and washed with rufous in places — in the extreme southeastern edge of the range of the species : Alor Island and Sumba;

 

- moulting from rufous into white plumage — collected in North Bihar.

  

Possible interpretations of this phenomenon are : males may be polymorphic for rufous and white plumage colour; rufous birds may be sub-adults; and there may even be two sympatric species distinguishable only in the male.

  

Habitat and distribution

 

Asian paradise flycatchers inhabit thick forests and well-wooded habitats from Turkestan to Manchuria, all over India and Sri Lanka to the Malay Archipelago on the islands of Sumba and Alor. They are vagrant in Korea and Maldives, and regionally extinct in Singapore.

 

They are migratory and spend the winter season in tropical Asia. There are resident populations in southern India and Sri Lanka, hence both visiting migrants and the locally breeding subspecies occur in these areas in winter.

 

According to Linné’s first description Asian paradise flycatchers were only distributed in India. Later ornithologists observed this spectacular bird in other Asian countries, and based on differences in plumage of males described several subspecies, of which the following 14 are recognized today:

 

- T. p. paradisi (Linnaeus, 1758) breeds in central and southern India, central Bangladesh and south-western Myanmar; populations occurring in Sri Lanka in the winter season are non-breeding.

 

- T. p. leucogaster (Swainson, 1838) breeds in the western Tian Shan, in Afghanistan, in the north of Pakistan, in northwestern and central India, in Nepal’s western and central regions; populations occurring in the east of Pakistan and in the south of India migrate towards the foothills of the Himalayas in spring for breeding.

 

- T. p. affinis (Blyth, 1846) inhabits Malaysia and Sumatra.

 

- T. p. incei (Gould, 1852) breeds in eastern, northeastern and central China, in the Russian Far East and in the north of Korea; populations occurring in Southeast Asia are non-breeding.

 

- T. p. insularis (Salvadori, 1887) inhabits the island Nias off the western coast of Sumatra.

 

- T. p. nicobarica (Oates, 1890) inhabits the Nicobar Islands.

 

- T. p. sumbaensis (Meyer, 1894) inhabits the Lesser Sunda Island Sumba.

 

- T. p. floris (Büttikofer, 1894) inhabits the Lesser Sunda Islands Sumbawa, Flores, Lomblen and Alor Island.

 

- T. p. procera (Richmond, 1903) inhabits the island Simeuluë northwest off the coast of Sumatra.

 

- T. p. ceylonensis (Zarudny & Harms, 1912) inhabits Sri Lanka.

 

- T. p. borneensis (Hartert, 1916) inhabits Borneo.

 

- T. p. saturatior (Salomonsen, 1933) breeds in the eastern parts of Nepal and northeastern India, in eastern Bangladesh and northern Myanmar; populations occurring in Malaysia migrate northward for breeding.[9]

 

- T. p. burmae (Salomonsen, 1933) inhabits the central region of Myanmar.

 

- T. p. indochinensis (Salomonsen, 1933) inhabits the eastern regions of Myanmar, Yunnan in the south of China, migrates through Thailand and Indochina to Malaysia, Sumatra and the neighboring islands.

  

Ecology and behaviour

 

Asian paradise flycatchers are noisy birds uttering sharp skreek calls. They have short legs and sit very upright whilst perched prominently, like a shrike. They are insectivorous and hunt in flight in the understorey. In the afternoons they dive from perches to bathe in small pools of water.

 

The breeding season lasts from May to July. Being socially monogamous both male and female take part in nest-building, incubation, brooding and feeding of the young. The incubation period lasts 14 to 16 days and the nestling period 9 to 12 days. Three or four eggs are laid in a neat cup nest made with twigs and spider webs on the end of a low branch. The nest is sometimes built in the vicinity of a breeding pair of drongos, which keep predators away. Chicks hatch in about 21 to 23 days. A case of interspecific feeding has been noted with paradise flycatcher chicks fed by Oriental white-eyes.

 

[Credit: en.wikipedia.org/]

This small Owl was spotted on board the Mignon between Maldives and Socotra in the piracy infested waters. About 20-25 cm high.

Scops owls are Strigidae (typical owls) mostly belonging to the genus Otus. Approximately 45 living species are known, but new ones are frequently recognized and unknown ones are still being discovered every few years or so, especially in Indonesia. For most of the 20th century, this genus included the American screech owls, which are now again separated in Megascops based on a range of behavioral, biogeographical, morphological and DNA sequence data. Otus is the largest genus of owls in terms of number of species.

 

Scops owls in the modern sense are restricted to the Old World. A single North American species, the Flammulated Owl, was provisionally placed in Otus and has now been moved to its own monotypic genus. See below for details.

 

As usual for owls, female scops owls are usually larger than the males of their species, with owls of both sexes being compact in size and shape. All of the birds in this genus are small and agile. Scops-owls are colored in various brownish hues, sometimes with a lighter underside and/or face, which helps to camouflage them against the bark of trees. Some are polymorphic, occurring in a greyish- and a reddish-brown morph.

 

They will be playful and drink nectar but nearby dangers' lurk... there are preying mantis, birds and butterfly-eating giant spiders! Torn and tattered they will keep on flying from place to place seemingly carefree enjoying life to the fullest, thus making the most of their relatively short life span + when summer begins to lean their lives are coming to an end - but then a new generation of caterpillars will soon emerge from the eggs distributed widely by the butterflies during the summer!

 

Papilio memnon, also called Great Memnon is a butterfly from Australasia. The first description was in 1758 by Linnaeus of Sweden. It is a large butterfly that belongs to the swallowtail family and it is widely distributed and with thirteen subspecies.

 

Larvae feed on citrus species, particularly pomelo (citrus grandis) and common lime (citrus aurantifolia) which are broadly cultivated across Asia. Adults lay single eggs on the underside of leaves, which hatch in three days. For the first four instars, caterpillars resemble bird droppings. Pupation occurs after about 2.5 weeks. Adults inhabit forest clearings and disturbed areas, eating nectar from a wide variety of flowering species.

 

Alfred Russel Wallace first described the remarkable polymorphic nature of P. memnon, which exists as 13 subspecies and in addition, females show a large diversity of morphological and coloration forms, many of which are mimetic of other unpalatable papilionid species (Batesian mimicry). Female morphological variations include: presence or absence of tails, hindwing pattern, forewing pattern, color of the basal triangle on the forewing, and abdomen color. Extensive study of this species has contributed insight into the genetic determination of mimicry. These studies give classic evidence for existence of a “supergene” complex, which slowly built up over the course of evolution allowing butterfly species to mimic their models very accurately. This complex includes multiple linked genes that control the morphological variations listed above via genetic crossover, rather than these traits diversifying individually by point mutations, or other genetic mechanism.

EOL/Encyclopedia of Life

 

Range

North-eastern India (including Sikkim, Assam and Nagaland), Nepal, Bangladesh, Bhutan, Myanmar, Nicobar Islands, Andaman Islands (stragglers only), western, southern and eastern China (including Hainan), Taiwan and southern Japan, Ryukyu Islands, Thailand, Laos, Vietnam, Kampuchea, Malaysia, and Indonesia (Sumatra, Mentawai Islands, Nias, Batu, Simeulue, Bangka, Java, Kalimantan, and the Lesser Sunda Islands).

Wikipedia

This mocker swallowtail butterfly (Papilio dardanus), native to sub-Saharan Africa, was seen yesterday in the 2014 Butterflies Live! exhibit at Lewis Ginter Botanical Garden. Males have a generally uniform appearance, but there are at least 14 varieties, or morphs, of the polymorphic females, with differences in wing shapes, colors, and markings; botanical garden staff identified this as a male, so I now know the mocker swallowtail in the preceding photo is one of the female variants.

 

Press "L" for larger image, on black.

Little angle taking a breather before fluttering away

Love is like a butterfly, it goes where it pleases and it pleases wherever it goes.

Love is like a butterfly, hold it too tight, it'll crush. Hold it too loose, it'll fly.

 

The Great Eggfly (Hypolimnas bolina), also called Blue Moon Butterfly in New Zealand or Common Eggfly,is a species of nymphalid butterfly.

The Great Eggfly is a black-bodied butterfly with a wingspan of about 7–8½ cm. The species has a high degree of sexual dimorphism. The female is mimetic with multiple morphs.

MaleThe upper side of the wings are jet black, offset with three pairs of white spots – two on the forewing and one on the hind. These white spots are surrounded by purple iridescence. In addition, the upper side of the hind wing bears a series of small white dots.

Female The upper side of the wings of the female is a brownish black and does not have any spots like those of the male. The edges bear white markings which are similar to those of the Common Indian Crow.

To the west the female is monomorphic, mimicking species of the oriental and Australasian danaid genus Euploea. Eastwards H. bolina is frequently polymorphic and most forms are then non-mimetic. In areas where it resembles Euploea the butterfly has usually been designated a Batesian mimic.

Great Eggflies are known for maternal care, with the females guarding leaves where eggs have been laid. Males are also very territorial and site fidelity increases with age.Territories that enhance the detection of females are preferred.The female hovers over a plant to check for ants which will eat her eggs. After selecting a plant which has no ants on it, she lays at least one but often two to five eggs on the undersides of the leaves.

This picture is showing my new website pierre-nizet.fr/ and it will be the last one I upload here.

 

The upper part showing you the desktop version.

At the Bottom, you can see th mobile version.

 

My motivations to leave flickr are numerous and polymorphic. But the biggest one is my willing to have control on the storage, datas and the presentation of my pictures.

 

To follow me, many ways are possible :

* Check my website often : pierre-nizet.fr/

* The old fashion one : RSS pierre-nizet.fr/feed/content/recent.rss

* Twitter : twitter.com/niz___

  

Bye bye

Great Mormon (Papilio memnon) is a large butterfly with contrasting colors that belongs to the Swallowtail family. A common South-Asian butterfly, it is widely distributed and has thirteen subspecies. The female is polymorphic and with mimetic forms.

 

Source: Wikipedia

Innenpark. Bonifatius-Felsen. Felsen am Bonifatiusweg,

Inner Park. Boniface Rock. Rock on the Boniface-Way

 

Asplenium trichomanes subsp. pachyrachis (Christ) Lovis et Reichst.

Willdenowia 10: 18. 1980.

 

Asplenium trichomanes sublus. pachyrachis Christ

Farnkr. Schweiz 1 (2): 92. 1900.

Asplenium csikii Kümmerle & András.

Magyar Bot. Lapok 17. 110. 1919 (nomen), 20. 3, fig. 1923

Asplenium pachyrhachis Landolt

Fl. Indicativa 268 2010.

 

Seestern-Braunschwarz-Streifenfarn, Dickstieliger Braunstieliger Streifenfarn, Dickstieliger Brauner Streifenfarn

Lobed Maidenhair Spleenwort

 

Anmerkung:

Die Asplenium trichomanes Gruppe, ist ein sehr polymorpher, taxonomisch kritischer Spezieskomplex! Die Evolutionsgeschichte und Beziehungen zwischen den Taxa in dieser Gruppe wurden intensiv untersucht. Allerdings sind morphologische Variation und die Verteilung dieser Taxa unzureichend bekannt, da sie in der lokalen Floren oder Checklisten häufig nicht vorkommen. Die Gründe für die Vernachlässigung der Taxa innerhalb der Asplenium trichomanes Gruppe sind der Mangel an diagnostischen morphologische Merkmalen, das häufige gemeinsame Auftreten an ihren Standorten, sowie die Hybridisierung unter den Taxa. Die Asplenium trichomanes Gruppe umfasst zytologisch und ökologisch unterschiedliche Taxa mit fast weltweiter Verbreitung, die offenbar noch aktiv in der Entwicklung sind (L. Ekrt & M. Štech, 2008).

 

Annotation:

The Asplenium trichomanes group is a very polymorphic, taxonomically critical species complex! The evolutionary history and relationships between the taxa in this group have been extensively studied. However, morphological variation and distribution of these taxa are poorly understood because they are often absent in local floras or checklists. The reasons for the neglect of the taxa within the Asplenium trichomanes group are the lack of diagnostic morphological features, the frequent common occurrence at their sites, as well as the hybridization among the taxa. The Asplenium trichomanes group includes cytologically and ecologically diverse taxa with almost worldwide distribution, which apparently are still active in development (L. Ekrt & M. Štech, 2008).

কালিম । Common Mormon (Papilio polytes)

A common species of swallowtail butterfly widely distributed across Asia. Seen round the year throughout India from plains up to 2000m. This butterfly is known for the mimicry displayed by the numerous polymorphic forms of its females.

 

Family : PAPILIONIDAE

 

Durgapur

Butterflies of Bengal, India

Common Mormon Butterfly (Papilio polytes)

 

Papilio polytes, the common Mormon, is a common species of swallowtail butterfly widely distributed across Asia.

 

This butterfly is known for the mimicry displayed by the numerous forms of its females which mimic inedible red-bodied swallowtails, such as the common rose and the crimson rose.

 

Jet black butterfly with row of white spots along the middle part of hindwing. 90–100 mm.

 

Male

The male has one morph only. It is a dark-coloured swallow-tailed butterfly. The upper forewing has a series of white spots decreasing in size towards the apex. The upper hindwing has a complete discal band of elongated white spots. It may or may not have marginal red crescents. The males are generally smaller in size than the females but not always. Both male and all forms of the female of P. polytes can vary considerably in size depending on climatic region.

 

Female

The female of the common Mormon is polymorphic. In the Indian Subcontinent, it has three forms or morphs. These are as follows:

 

Form Cyrus is similar to the male, differing in that it always has strongly marked red crescents. It is the least common of the three forms. It is normally abundant where the common rose or crimson rose do not occur, such as in Himachal Pradesh around Shimla; although a few specimens of form romulus have also been caught alongside.

 

ThisFormeian female form of the common Mormon mimics the common rose very closely. This is the commonest form wherever the common rose flies.

 

This female form mimics the crimson rose and is common over its range. It is not such a close mimic as the previous form being duller than its model. It is easy to differentiate the mimics from models by the colour of their body—the models are red-bodied and the mimics are black-bodied.

 

The common Mormon prefers lightly wooded country, but is present everywhere and high up into the hills. It is a regular visitor to gardens, being especially abundant in orchards of its food plants—oranges and limes. It is most common in the monsoon and post-monsoon months.

www.lissongallery.com/exhibitions/anish-kapoor-f45a2ea5-2...

 

For his latest exhibition, Anish Kapoor presents a new series of paintings, an element of his practice that has rarely been seen, exploring the intimate and ritualistic nature of his work. Created over the past year, the show provides a poetic view of the artist's recent preoccupations. While painting has always been an integral part of Kapoor’s practice, this radical new body of work is both spiritual and ecstatic, showing Kapoor working in more vivid and urgent form than ever. Alongside this exhibition, a solo show dedicated to Kapoor's paintings will run at Modern Art Oxford from 2 October 2021 - 13 February 2022, and both shows precede Kapoor’s major retrospective at Gallerie dell'Accademia di Venezia, opening April 2022 to coincide with the Venice Biennale.

 

Through painting, Kapoor delves into the deep inner world of our mind and body, from the physical exploration of the flesh and blood, to investigating psychological concepts as primal and nameless as origin and obliteration. Since the 1980s, Kapoor has been celebrated largely as a sculptor, yet painting, and its rawest composition, colour and form, have been a fundamental element of his practice-. The presentation will feature a selection of new and recent paintings, created between 2019 and 2021, the majority in the artist’s London-based studio during the pandemic. Like the artist’s wider oeuvre, these paintings are rooted in a drive to grasp the unknown, to awaken consciousness and experiment with the phenomenology of space.

 

Kapoor’s work has been characterized by an intense encounter with colour and matter – manifest either through refined, reflective surfaces such as metal or mirrors, or through the tactile, sensual quality of the blankets of impasto. The magnetism of the colour red is evident in these new paintings, manifesting the elemental force that flows through us all, yet now accompanied by a new palette of telluric greys and yellows, as if witnessing a surge from the depths of the earth. Some works appear volcanic, with an intense, fiery energy, while others are more primitive and abstract, with layers of dense pigment and resin forming a sculpted solidity. Many of the paintings have a visceral outpouring where a canvas within a canvas rotates and evolves in space, seeming to defy gravity, with brushstrokes cascading over the edges like a waterfall. In others we see distorted, polymorphic figures emerging from a deep, radiant void, with a ghostly aura.

 

Kapoor achieves a coherence of mind and body, of interior and exterior in two of the series of works, illustrating a mythic landscape with a turbulent, ominous atmosphere that differentiates land from sky, body from space. These whirling landscapes evoke the extraordinary, eerie Romanticism of JMW Turner, a worship of nature marked through an expressive, dramatic scene. Similar in disposition are two works where we imagine the moon rising over the peak – a symbolic narrative of a new cycle, of origins and menstruation.

 

The wall-based paintings recall some of Kapoor’s most ambitious, distinguished works, including Svayambhu (2007), My Red Homeland (2003) and Symphony for a Beloved Sun (2013). In these floor-based works we see a more ritualistic, visceral language, where Kapoor unashamedly delves into depicting the very blood and flesh from which we are all born. Artists from Leonardo di Vinci to Francis Bacon have been fascinated with the innards of the body, be it our anatomy or the surrealist beauty in violence. The work also stands in a powerful tradition of artists exploring the human body’s expression of divine matters, yet through the unique vision of Kapoor’s Eastern and Western influences, and ---– considering the year in which they were created --– taking on new meaning highlighting the fragility of the body and self.

Maize (/meɪz/ MAYZ; Zea mays subsp. mays, from Spanish: maíz after Taino: mahiz), also known as corn (North American and Australian English), is a cereal grain first domesticated by indigenous peoples in southern Mexico about 10,000 years ago. The leafy stalk of the plant produces pollen inflorescences and separate ovuliferous inflorescences called ears that yield kernels or seeds, which are fruits.

 

Maize has become a staple food in many parts of the world, with the total production of maize surpassing that of wheat or rice. In addition to being consumed directly by humans (often in the form of masa), maize is also used for corn ethanol, animal feed and other maize products, such as corn starch and corn syrup. The six major types of maize are dent corn, flint corn, pod corn, popcorn, flour corn, and sweet corn.[5] Sugar-rich varieties called sweet corn are usually grown for human consumption as kernels, while field corn varieties are used for animal feed, various corn-based human food uses (including grinding into cornmeal or masa, pressing into corn oil, and fermentation and distillation into alcoholic beverages like bourbon whiskey), and as chemical feedstocks. Maize is also used in making ethanol and other biofuels.

 

Maize is widely cultivated throughout the world, and a greater weight of maize is produced each year than any other grain. In 2014, total world production was 1.04 billion tonnes. Maize is the most widely grown grain crop throughout the Americas, with 361 million metric tons grown in the United States alone in 2014. Genetically modified maize made up 85% of the maize planted in the United States in 2009. Subsidies in the United States help to account for its high level of cultivation of maize and its position as the largest producer in the world.

 

HISTORY

PRE-COLUMBIAN DEVELOPMENT

Maize is a cultigen; human intervention is required for it to propagate. Whether or not the kernels fall off the cob on their own is a key piece of evidence used in archaeology to distinguish domesticated maize from its naturally-propagating teosinte ancestor. Genetic evidence can also be used to determine when various lineages split.

 

Most historians believe maize was domesticated in the Tehuacán Valley of Mexico. Recent research in the early 21st century has modified this view somewhat; scholars now indicate the adjacent Balsas River Valley of south-central Mexico as the center of domestication.

 

An influential 2002 study by Matsuoka et al. has demonstrated that, rather than the multiple independent domestications model, all maize arose from a single domestication in southern Mexico about 9,000 years ago. The study also demonstrated that the oldest surviving maize types are those of the Mexican highlands. Later, maize spread from this region over the Americas along two major paths. This is consistent with a model based on the archaeological record suggesting that maize diversified in the highlands of Mexico before spreading to the lowlands.

 

Archaeologist Dolores Piperno has said:

 

A large corpus of data indicates that [maize] was dispersed into lower Central America by 7600 BP [5600 BC] and had moved into the inter-Andean valleys of Colombia between 7000 and 6000 BP [5000–4000 BC].

— Dolores Piperno, The Origins of Plant Cultivation and Domestication in the New World Tropics: Patterns, Process, and New Developments

 

Since then, even earlier dates have been published.

 

According to a genetic study by Embrapa, corn cultivation was introduced in South America from Mexico, in two great waves: the first, more than 6000 years ago, spread through the Andes. Evidence of cultivation in Peru has been found dating to about 6700 years ago. The second wave, about 2000 years ago, through the lowlands of South America.

 

The earliest maize plants grew only small, 25-millimetre-long (1 in) corn cobs, and only one per plant. In Jackson Spielvogel's view, many centuries of artificial selection (rather than the current view that maize was exploited by interplanting with teosinte) by the indigenous people of the Americas resulted in the development of maize plants capable of growing several cobs per plant, which were usually several centimetres/inches long each. The Olmec and Maya cultivated maize in numerous varieties throughout Mesoamerica; they cooked, ground and processed it through nixtamalization. It was believed that beginning about 2500 BC, the crop spread through much of the Americas. Research of the 21st century has established even earlier dates. The region developed a trade network based on surplus and varieties of maize crops.

 

Mapuches of south-central Chile cultivated maize along with quinoa and potatoes in pre-Hispanic times; however, potato was the staple food of most Mapuches, "specially in the southern and coastal [Mapuche] territories where maize did not reach maturity". Before the expansion of the Inca Empire maize was traded and transported as far south as 40°19' S in Melinquina, Lácar Department. In that location maize remains were found inside pottery dated to 730 ± 80 BP and 920 ± 60 BP. Probably this maize was brought across the Andes from Chile. The presence of maize in Guaitecas Archipelago (43°55' S), the southernmost outpost of pre-Hispanic agriculture, is reported by early Spanish explorers. However the Spanish may have misidentified the plant.

 

COLUMBIAN EXCHANGE

After the arrival of Europeans in 1492, Spanish settlers consumed maize, and explorers and traders carried it back to Europe and introduced it to other countries. Spanish settlers far preferred wheat bread to maize, cassava, or potatoes. Maize flour could not be substituted for wheat for communion bread, since in Christian belief only wheat could undergo transubstantiation and be transformed into the body of Christ. Some Spaniards worried that by eating indigenous foods, which they did not consider nutritious, they would weaken and risk turning into Indians. "In the view of Europeans, it was the food they ate, even more than the environment in which they lived, that gave Amerindians and Spaniards both their distinctive physical characteristics and their characteristic personalities." Despite these worries, Spaniards did consume maize. Archeological evidence from Florida sites indicate they cultivated it as well.

 

Maize spread to the rest of the world because of its ability to grow in diverse climates. It was cultivated in Spain just a few decades after Columbus's voyages and then spread to Italy, West Africa and elsewhere. Widespread cultivation most likely began in southern Spain in 1525, after which it quickly spread to the rest of the Spanish Empire including its territories in Italy (and, from there, to other Italian states). Maize had many advantages over wheat and barley; it yielded two and a half times the food energy per unit cultivated area, could be harvested in successive years from the same plot of land, and grew in wildly varying altitudes and climates, from relatively dry regions with only 250 mm (10 in) of annual rainfall to damp regions with over 5,000 mm (200 in). By the 17th century it was a common peasant food in Southwestern Europe, including Portugal, Spain, southern France, and Italy. By the 18th century, it was the chief food of the southern French and Italian peasantry, especially in the form of polenta in Italy.

Names

 

The word maize derives from the Spanish form of the indigenous Taíno word for the plant, mahiz. It is known by other names around the world.

 

The word "corn" outside the US, Canada, Australia, and New Zealand refers to any cereal crop, its meaning understood to vary geographically to refer to the local staple. In the United States,[30] Canada, Australia, and New Zealand, corn primarily means maize; this usage started as a shortening of "Indian corn". "Indian corn" primarily means maize (the staple grain of indigenous Americans), but can refer more specifically to multicolored "flint corn" used for decoration.

 

In places outside the US, Canada, Australia, and New Zealand, corn often refers to maize in culinary contexts. The narrower meaning is usually indicated by some additional word, as in sweet corn, sweetcorn, corn on the cob, baby corn, the puffed confection known as popcorn and the breakfast cereal known as corn flakes.

 

In Southern Africa, maize is commonly called mielie (Afrikaans) or mealie (English), words derived from the Portuguese word for maize, milho.

 

Maize is preferred in formal, scientific, and international usage because it refers specifically to this one grain, unlike corn, which has a complex variety of meanings that vary by context and geographic region. Maize is used by agricultural bodies and research institutes such as the FAO and CSIRO. National agricultural and industry associations often include the word maize in their name even in English-speaking countries where the local, informal word is something other than maize; for example, the Maize Association of Australia, the Indian Maize Development Association, the Kenya Maize Consortium and Maize Breeders Network, the National Maize Association of Nigeria, the Zimbabwe Seed Maize Association.

 

STRUCTURE AND PHYSIOLOGY

The maize plant is often 3 m (10 ft) in height, though some natural strains can grow 13 m (43 ft). The stem is commonly composed of 20 internodes of 18 cm (7 in) length. The leaves arise from the nodes, alternately on opposite sides on the stalk. A leaf, which grows from each node, is generally 9 cm (3+1⁄2 in) in width and 120 cm (3 ft 11 in) in length.

 

Ears develop above a few of the leaves in the midsection of the plant, between the stem and leaf sheath, elongating by around 3 mm (1⁄8 in) per day, to a length of 18 cm (7 in) with 60 cm (24 in) being the maximum alleged in the subspecies. They are female inflorescences, tightly enveloped by several layers of ear leaves commonly called husks. Certain varieties of maize have been bred to produce many additional developed ears. These are the source of the "baby corn" used as a vegetable in Asian cuisine.

 

The apex of the stem ends in the tassel, an inflorescence of male flowers. When the tassel is mature and conditions are suitably warm and dry, anthers on the tassel dehisce and release pollen. Maize pollen is anemophilous (dispersed by wind), and because of its large settling velocity, most pollen falls within a few meters of the tassel.

 

Elongated stigmas, called silks, emerge from the whorl of husk leaves at the end of the ear. They are often pale yellow and 18 cm (7 in) in length, like tufts of hair in appearance. At the end of each is a carpel, which may develop into a "kernel" if fertilized by a pollen grain. The pericarp of the fruit is fused with the seed coat referred to as "caryopsis", typical of the grasses, and the entire kernel is often referred to as the "seed". The cob is close to a multiple fruit in structure, except that the individual fruits (the kernels) never fuse into a single mass. The grains are about the size of peas, and adhere in regular rows around a white, pithy substance, which forms the ear. The maximum size of kernels is reputedly 2.5 cm (1 in). An ear commonly holds 600 kernels. They are of various colors: blackish, bluish-gray, purple, green, red, white and yellow. When ground into flour, maize yields more flour with much less bran than wheat does. It lacks the protein gluten of wheat and, therefore, makes baked goods with poor rising capability. A genetic variant that accumulates more sugar and less starch in the ear is consumed as a vegetable and is called sweet corn. Young ears can be consumed raw, with the cob and silk, but as the plant matures (usually during the summer months), the cob becomes tougher and the silk dries to inedibility. By the end of the growing season, the kernels dry out and become difficult to chew without cooking them tender first in boiling water.

 

Planting density affects multiple aspects of maize. Modern farming techniques in developed countries usually rely on dense planting, which produces one ear per stalk. Stands of silage maize are yet denser,[citation needed] and achieve a lower percentage of ears and more plant matter.

 

Maize is a facultative short-day plant and flowers in a certain number of growing degree days > 10 °C (50 °F) in the environment to which it is adapted. The magnitude of the influence that long nights have on the number of days that must pass before maize flowers is genetically prescribed and regulated by the phytochrome system.

Photoperiodicity can be eccentric in tropical cultivars such that the long days characteristic of higher latitudes allow the plants to grow so tall that they do not have enough time to produce seed before being killed by frost. These attributes, however, may prove useful in using tropical maize for biofuels.

 

Immature maize shoots accumulate a powerful antibiotic substance, 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA). DIMBOA is a member of a group of hydroxamic acids (also known as benzoxazinoids) that serve as a natural defense against a wide range of pests, including insects, pathogenic fungi and bacteria. DIMBOA is also found in related grasses, particularly wheat. A maize mutant (bx) lacking DIMBOA is highly susceptible to attack by aphids and fungi. DIMBOA is also responsible for the relative resistance of immature maize to the European corn borer (family Crambidae). As maize matures, DIMBOA levels and resistance to the corn borer decline.

 

Because of its shallow roots, maize is susceptible to droughts, intolerant of nutrient-deficient soils, and prone to be uprooted by severe winds.

 

While yellow maizes derive their color from lutein and zeaxanthin, in red-colored maizes, the kernel coloration is due to anthocyanins and phlobaphenes. These latter substances are synthesized in the flavonoids synthetic pathway from polymerization of flavan-4-ols by the expression of maize pericarp color1 (p1) gene which encodes an R2R3 myb-like transcriptional activator of the A1 gene encoding for the dihydroflavonol 4-reductase (reducing dihydroflavonols into flavan-4-ols) while another gene (Suppressor of Pericarp Pigmentation 1 or SPP1) acts as a suppressor. The p1 gene encodes an Myb-homologous transcriptional activator of genes required for biosynthesis of red phlobaphene pigments, while the P1-wr allele specifies colorless kernel pericarp and red cobs, and unstable factor for orange1 (Ufo1) modifies P1-wr expression to confer pigmentation in kernel pericarp, as well as vegetative tissues, which normally do not accumulate significant amounts of phlobaphene pigments. The maize P gene encodes a Myb homolog that recognizes the sequence CCT/AACC, in sharp contrast with the C/TAACGG bound by vertebrate Myb proteins.

 

The ear leaf is the leaf most closely associated with a particular developing ear. This leaf and above contribute 70%[57] to 75% to 90% of grain fill. Therefore fungicide application is most important in that region in most disease environments.

 

ABNORMAL FLOWERS

Maize flowers may sometimes exhibit mutations that lead to the formation of female flowers in the tassel. These mutations, ts4 and Ts6, prohibit the development of the stamen while simultaneously promoting pistil development. This may cause inflorescences containing both male and female flowers, or hermaphrodite flowers.

 

GENETICS

Maize is an annual grass in the family Gramineae, which includes such plants as wheat, rye, barley, rice, sorghum, and sugarcane. There are two major species of the genus Zea (out of six total): Zea mays (maize) and Zea diploperennis, which is a perennial type of teosinte. The annual teosinte variety called Zea mays mexicana is the closest botanical relative to maize. It still grows in the wild as an annual in Mexico and Guatemala.

 

Many forms of maize are used for food, sometimes classified as various subspecies related to the amount of starch each has:

 

Flour corn: Zea mays var. amylacea

Popcorn: Zea mays var. everta

Dent corn : Zea mays var. indentata

Flint corn: Zea mays var. indurata

Sweet corn: Zea mays var. saccharata and Zea mays var. rugosa

Waxy corn: Zea mays var. ceratina

Amylomaize: Zea mays

Pod corn: Zea mays var. tunicata Larrañaga ex A. St. Hil.

Striped maize: Zea mays var. japonica

 

This system has been replaced (though not entirely displaced) over the last 60 years by multivariable classifications based on ever more data. Agronomic data were supplemented by botanical traits for a robust initial classification, then genetic, cytological, protein and DNA evidence was added. Now, the categories are forms (little used), races, racial complexes, and recently branches.

 

Maize is a diploid with 20 chromosomes (n=10). The combined length of the chromosomes is 1500 cM. Some of the maize chromosomes have what are known as "chromosomal knobs": highly repetitive heterochromatic domains that stain darkly. Individual knobs are polymorphic among strains of both maize and teosinte.

 

Barbara McClintock used these knob markers to validate her transposon theory of "jumping genes", for which she won the 1983 Nobel Prize in Physiology or Medicine. Maize is still an important model organism for genetics and developmental biology today.

 

The centromeres have two types of structural components, both of which are found only in the centromeres: Large arrays of CentC, a short satellite DNA; and a few of a family of retrotransposons. The B chromosome, unlike the others, contains an additional repeat which extends into neighboring areas of the chromosome. Centromeres can accidentally shrink during division and still function, although it is thought this will fail if it shrinks below a few hundred kilobase. Kinetochores contain RNA originating from centromeres. Centromere regions can become inactive, and can continue in that state if the chromosome still has another active one.

 

The Maize Genetics Cooperation Stock Center, funded by the USDA Agricultural Research Service and located in the Department of Crop Sciences at the University of Illinois at Urbana-Champaign, is a stock center of maize mutants. The total collection has nearly 80,000 samples. The bulk of the collection consists of several hundred named genes, plus additional gene combinations and other heritable variants. There are about 1000 chromosomal aberrations (e.g., translocations and inversions) and stocks with abnormal chromosome numbers (e.g., tetraploids). Genetic data describing the maize mutant stocks as well as myriad other data about maize genetics can be accessed at MaizeGDB, the Maize Genetics and Genomics Database.

 

In 2005, the US National Science Foundation (NSF), Department of Agriculture (USDA) and the Department of Energy (DOE) formed a consortium to sequence the B73 maize genome. The resulting DNA sequence data was deposited immediately into GenBank, a public repository for genome-sequence data. Sequences and genome annotations have also been made available throughout the project's lifetime at the project's official site.

 

Primary sequencing of the maize genome was completed in 2008. On November 20, 2009, the consortium published results of its sequencing effort in Science. The genome, 85% of which is composed of transposons, was found to contain 32,540 genes (By comparison, the human genome contains about 2.9 billion bases and 26,000 genes). Much of the maize genome has been duplicated and reshuffled by helitrons—group of rolling circle transposons.

 

In Z. mays and various other angiosperms the MADS-box motif is involved in floral development. Early study in several angiosperm models including Z. mays was the beginning of research into the molecular evolution of floral structure in general, as well as their role in nonflowering plants.

 

EVOLUTION

As with many plants and animals, Z. mays has a positive correlation between effective population size and the magnitude of selection pressure. Z. m. having an EPS of ~650,000, it clusters with others of about the same EPS, and has 79% of its amino acid sites under selection.

 

Recombination is a significant source of diversity in Z. mays. (Note that this finding supersedes previous studies which showed no such correlation.)

 

This recombination/diversity effect is seen throughout plants but is also found to not occur – or not as strongly – in regions of high gene density. This is likely the reason that domesticated Z. mays has not seen as much of an increase in diversity within areas of higher density as in regions of lower density, although there is more evidence in other plants.

 

Some lines of maize have undergone ancient polyploidy events, starting 11m years ago. Over that time ~72% of polyploid duplicated genes have been retained, which is higher than other plants with older polyploidy events. Thus maize may be due to lose more duplicate genes as time goes along, similar to the course followed by the genomes of other plants. If so - if gene loss has merely not occurred yet - that could explain the lack of observed positive selection and lower negative selection which are observed in otherwise similar plants, i.e. also naturally outcrossing and with similar effective population sizes.

 

Ploidy does not appear to influence EPS or magnitude of selection effect in maize.

 

BREEDING

Maize reproduces sexually each year. This randomly selects half the genes from a given plant to propagate to the next generation, meaning that desirable traits found in the crop (like high yield or good nutrition) can be lost in subsequent generations unless certain techniques are used.

 

Maize breeding in prehistory resulted in large plants producing large ears. Modern breeding began with individuals who selected highly productive varieties in their fields and then sold seed to other farmers. James L. Reid was one of the earliest and most successful developing Reid's Yellow Dent in the 1860s. These early efforts were based on mass selection. Later breeding efforts included ear to row selection (C. G. Hopkins c. 1896), hybrids made from selected inbred lines (G. H. Shull, 1909), and the highly successful double cross hybrids using four inbred lines (D. F. Jones c. 1918, 1922). University supported breeding programs were especially important in developing and introducing modern hybrids. By the 1930s, companies such as Pioneer devoted to production of hybrid maize had begun to influence long-term development. Internationally important seed banks such as the International Maize and Wheat Improvement Center (CIMMYT) and the US bank at the Maize Genetics Cooperation Stock Center University of Illinois at Urbana-Champaign maintain germplasm important for future crop development.

 

Since the 1940s the best strains of maize have been first-generation hybrids made from inbred strains that have been optimized for specific traits, such as yield, nutrition, drought, pest and disease tolerance. Both conventional cross-breeding and genetic modification have succeeded in increasing output and reducing the need for cropland, pesticides, water and fertilizer. There is conflicting evidence to support the hypothesis that maize yield potential has increased over the past few decades. This suggests that changes in yield potential are associated with leaf angle, lodging resistance, tolerance of high plant density, disease/pest tolerance, and other agronomic traits rather than increase of yield potential per individual plant.

 

Tropical landraces remain an important and underutilized source of resistance alleles for for disease and for herbivores. Notable discoveries of rare alleles for this purpose were made by Dao et al 2014 and Sood et al 2014.

 

GLOBAL PROGRAM

CIMMYT operates a conventional breeding program to provide optimized strains. The program began in the 1980s. Hybrid seeds are distributed in Africa by the Drought Tolerant Maize for Africa project.

 

GENETIC MODIFICATION

Genetically modified (GM) maize was one of the 26 GM crops grown commercially in 2016. The vast majority of this is Bt maize. Grown since 1997 in the United States and Canada, 92% of the US maize crop was genetically modified in 2016 and 33% of the worldwide maize crop was GM in 2016. As of 2011, Herbicide-tolerant maize varieties were grown in Argentina, Australia, Brazil, Canada, China, Colombia, El Salvador, the European Union, Honduras, Japan, Korea, Malaysia, Mexico, New Zealand, Philippines, the Russian Federation, Singapore, South Africa, Taiwan, Thailand, and the United States. Insect-resistant maize was grown in Argentina, Australia, Brazil, Canada, Chile, China, Colombia, Egypt, the European Union, Honduras, Japan, Korea, Malaysia, Mexico, New Zealand, Philippines, South Africa, Switzerland, Taiwan, the United States, and Uruguay.

 

In September 2000, up to $50 million worth of food products were recalled due to the presence of Starlink genetically modified corn, which had been approved only for animal consumption and had not been approved for human consumption, and was subsequently withdrawn from the market.

 

ORIGIN

Maize is the domesticated variant of teosinte. The two plants have dissimilar appearance, maize having a single tall stalk with multiple leaves and teosinte being a short, bushy plant. The difference between the two is largely controlled by differences in just two genes, called grassy tillers-1 (gt1, A0A317YEZ1) and teosinte branched-1 (tb1, Q93WI2).

 

Several theories had been proposed about the specific origin of maize in Mesoamerica:

 

It is a direct domestication of a Mexican annual teosinte, Zea mays ssp. parviglumis, native to the Balsas River valley in south-eastern Mexico, with up to 12% of its genetic material obtained from Zea mays ssp. mexicana through introgression.

It has been derived from hybridization between a small domesticated maize (a slightly changed form of a wild maize) and a teosinte of section Luxuriantes, either Z. luxurians or Z. diploperennis.

It has undergone two or more domestications either of a wild maize or of a teosinte. (The term "teosinte" describes all species and subspecies in the genus Zea, excluding Zea mays ssp. mays.)

It has evolved from a hybridization of Z. diploperennis by Tripsacum dactyloides.

 

In the late 1930s, Paul Mangelsdorf suggested that domesticated maize was the result of a hybridization event between an unknown wild maize and a species of Tripsacum, a related genus. This theory about the origin of maize has been refuted by modern genetic testing, which refutes Mangelsdorf's model and the fourth listed above. 

 

The teosinte origin theory was proposed by the Russian botanist Nikolai Ivanovich Vavilov in 1931 and the later American Nobel Prize-winner George Beadle in 1932.: 10  It is supported experimentally and by recent studies of the plants' genomes. Teosinte and maize can cross-breed and produce fertile offspring. A number of questions remain concerning the species, among them:

 

how the immense diversity of the species of sect. Zea originated,

how the tiny archaeological specimens of 3500–2700 BC could have been selected from a teosinte, and

how domestication could have proceeded without leaving remains of teosinte or maize with teosintoid traits earlier than the earliest known until recently, dating from ca. 1100 BC.

 

The domestication of maize is of particular interest to researchers—archaeologists, geneticists, ethnobotanists, geographers, etc. The process is thought by some to have started 7,500 to 12,000 years ago. Research from the 1950s to 1970s originally focused on the hypothesis that maize domestication occurred in the highlands between the states of Oaxaca and Jalisco, because the oldest archaeological remains of maize known at the time were found there.

Connection with 'parviglumis' subspecies

Genetic studies, published in 2004 by John Doebley, identified Zea mays ssp. parviglumis, native to the Balsas River valley in Mexico's southwestern highlands, and also known as Balsas teosinte, as being the crop wild relative that is genetically most similar to modern maize. This was confirmed by further studies, which refined this hypothesis somewhat. Archaeobotanical studies, published in 2009, point to the middle part of the Balsas River valley as the likely location of early domestication; this river is not very long, so these locations are not very distant. Stone milling tools with maize residue have been found in an 8,700 year old layer of deposits in a cave not far from Iguala, Guerrero.

 

Doebley was part of the team that first published, in 2002, that maize had been domesticated only once, about 9,000 years ago, and then spread throughout the Americas.

 

A primitive corn was being grown in southern Mexico, Central America, and northern South America 7,000 years ago. Archaeological remains of early maize ears, found at Guila Naquitz Cave in the Oaxaca Valley, date back roughly 6,250 years; the oldest ears from caves near Tehuacan, Puebla, 5,450 B.P.

 

Maize pollen dated to 7,300 B.P. from San Andres, Tabasco, on the Caribbean coast has also been recovered.

 

As maize was introduced to new cultures, new uses were developed and new varieties selected to better serve in those preparations. Maize was the staple food, or a major staple – along with squash, Andean region potato, quinoa, beans, and amaranth – of most pre-Columbian North American, Mesoamerican, South American, and Caribbean cultures. The Mesoamerican civilization, in particular, was deeply interrelated with maize. Its traditions and rituals involved all aspects of maize cultivation – from the planting to the food preparation. Maize formed the Mesoamerican people's identity.

 

It is unknown what precipitated its domestication, because the edible portion of the wild variety is too small, and hard to obtain, to be eaten directly, as each kernel is enclosed in a very hard bivalve shell.

 

In 1939, George Beadle demonstrated that the kernels of teosinte are readily "popped" for human consumption, like modern popcorn.[91] Some have argued it would have taken too many generations of selective breeding to produce large, compressed ears for efficient cultivation. However, studies of the hybrids readily made by intercrossing teosinte and modern maize suggest this objection is not well founded.

 

SPREADING TO THE NORTH

Around 4,500 ago, maize began to spread to the north; it was first cultivated in what is now the United States at several sites in New Mexico and Arizona, about 4,100 ago.

 

During the first millennium AD, maize cultivation spread more widely in the areas north. In particular, the large-scale adoption of maize agriculture and consumption in eastern North America took place about A.D. 900. Native Americans cleared large forest and grassland areas for the new crop.

 

In 2005, research by the USDA Forest Service suggested that the rise in maize cultivation 500 to 1,000 years ago in what is now the southeastern United States corresponded with a decline of freshwater mussels, which are very sensitive to environmental changes.

 

CULTIVATION

PLANTING

Because it is cold-intolerant, in the temperate zones maize must be planted in the spring. Its root system is generally shallow, so the plant is dependent on soil moisture. As a plant that uses C4 carbon fixation, maize is a considerably more water-efficient crop than plants that use C3 carbon fixation such as alfalfa and soybeans. Maize is most sensitive to drought at the time of silk emergence, when the flowers are ready for pollination. In the United States, a good harvest was traditionally predicted if the maize was "knee-high by the Fourth of July", although modern hybrids generally exceed this growth rate. Maize used for silage is harvested while the plant is green and the fruit immature. Sweet corn is harvested in the "milk stage", after pollination but before starch has formed, between late summer and early to mid-autumn. Field maize is left in the field until very late in the autumn to thoroughly dry the grain, and may, in fact, sometimes not be harvested until winter or even early spring. The importance of sufficient soil moisture is shown in many parts of Africa, where periodic drought regularly causes maize crop failure and consequent famine. Although it is grown mainly in wet, hot climates, it has been said to thrive in cold, hot, dry or wet conditions, meaning that it is an extremely versatile crop.

 

Maize was planted by the Native Americans in hills, in a complex system known to some as the Three Sisters. Maize provided support for beans, and the beans provided nitrogen derived from nitrogen-fixing rhizobia bacteria which live on the roots of beans and other legumes; and squashes provided ground cover to stop weeds and inhibit evaporation by providing shade over the soil. This method was replaced by single species hill planting where each hill 60–120 cm (2 ft 0 in–3 ft 11 in) apart was planted with three or four seeds, a method still used by home gardeners. A later technique was "checked maize", where hills were placed

 

1 m (40 in) apart in each direction, allowing cultivators to run through the field in two directions. In more arid lands, this was altered and seeds were planted in the bottom of 10–12 cm (4–4+1⁄2 in) deep furrows to collect water. Modern technique plants maize in rows which allows for cultivation while the plant is young, although the hill technique is still used in the maize fields of some Native American reservations. When maize is planted in rows, it also allows for planting of other crops between these rows to make more efficient use of land space.

 

In most regions today, maize grown in residential gardens is still often planted manually with a hoe, whereas maize grown commercially is no longer planted manually but rather is planted with a planter. In North America, fields are often planted in a two-crop rotation with a nitrogen-fixing crop, often alfalfa in cooler climates and soybeans in regions with longer summers. Sometimes a third crop, winter wheat, is added to the rotation.

 

Many of the maize varieties grown in the United States and Canada are hybrids. Often the varieties have been genetically modified to tolerate glyphosate or to provide protection against natural pests. Glyphosate is an herbicide which kills all plants except those with genetic tolerance. This genetic tolerance is very rarely found in nature.

 

In the midwestern United States, low-till or no-till farming techniques are usually used. In low-till, fields are covered once, maybe twice, with a tillage implement either ahead of crop planting or after the previous harvest. The fields are planted and fertilized. Weeds are controlled through the use of herbicides, and no cultivation tillage is done during the growing season. This technique reduces moisture evaporation from the soil, and thus provides more moisture for the crop. The technologies mentioned in the previous paragraph enable low-till and no-till farming. Weeds compete with the crop for moisture and nutrients, making them undesirable.

 

HARVESTING

Before the 20th century, all maize harvesting was by manual labour, by grazing, or by some combination of those. Whether the ears were hand-picked and the stover was grazed, or the whole plant was cut, gathered, and shocked, people and livestock did all the work. Between the 1890s and the 1970s, the technology of maize harvesting expanded greatly. Today, all such technologies, from entirely manual harvesting to entirely mechanized, are still in use to some degree, as appropriate to each farm's needs, although the thoroughly mechanized versions predominate, as they offer the lowest unit costs when scaled to large farm operations. For small farms, their unit cost can be too high, as their higher fixed cost cannot be amortized over as many units.[citation needed]

 

Before World War II, most maize in North America was harvested by hand. This involved a large number of workers and associated social events (husking or shucking bees). From the 1890s onward, some machinery became available to partially mechanize the processes, such as one- and two-row mechanical pickers (picking the ear, leaving the stover) and corn binders, which are reaper-binders designed specifically for maize (for example, Video on YouTube). The latter produce sheaves that can be shocked. By hand or mechanical picker, the entire ear is harvested, which then requires a separate operation of a maize sheller to remove the kernels from the ear. Whole ears of maize were often stored in corn cribs, and these whole ears are a sufficient form for some livestock feeding use. Today corn cribs with whole ears, and corn binders, are less common because most modern farms harvest the grain from the field with a combine and store it in bins. The combine with a corn head (with points and snap rolls instead of a reel) does not cut the stalk; it simply pulls the stalk down. The stalk continues downward and is crumpled into a mangled pile on the ground, where it usually is left to become organic matter for the soil. The ear of maize is too large to pass between slots in a plate as the snap rolls pull the stalk away, leaving only the ear and husk to enter the machinery. The combine separates the husk and the cob, keeping only the kernels.

When maize is a silage crop, the entire plant is usually chopped at once with a forage harvester (chopper) and ensiled in silos or polymer wrappers. Ensiling of sheaves cut by a corn binder was formerly common in some regions but has become uncommon. For storing grain in bins, the moisture of the grain must be sufficiently low to avoid spoiling. If the moisture content of the harvested grain is too high, grain dryers are used to reduce the moisture content by blowing heated air through the grain. This can require large amounts of energy in the form of combustible gases (propane or natural gas) and electricity to power the blowers.

 

PRODUCTION

Maize is widely cultivated throughout the world, and a greater weight of maize is produced each year than any other grain. In 2018, total world production was 1.15 billion tonnes, led by the United States with 34.2% of the total (table). China produced 22.4% of the global total.

 

UNITED STATES

In 2016, maize production was forecast to be over 380 million metric tons (15 billion bushels), an increase of 11% over 2014 American production. Based on conditions as of August 2016, the expected yield would be the highest ever for the United States. The area of harvested maize was forecast to be 35 million hectares (87 million acres), an increase of 7% over 2015. Maize is especially popular in Midwestern states such as Indiana, Iowa, and Illinois; in the latter, it was named the state's official grain in 2017.

 

STORAGE

Drying is vital to prevent or at least reduce mycotoxin contamination. Aspergillus and Fusarium spp. are the most common mycotoxin sources, but there are others. Altogether maize contaminants are so common, and this crop is so economically important, that maize mycotoxins are among the most important in agriculture in general.

 

USES

HUMAN FOOD

Maize and cornmeal (ground dried maize) constitute a staple food in many regions of the world. Maize is used to produce cornstarch, a common ingredient in home cooking and many industrialized food products. Maize starch can be hydrolyzed and enzymatically treated to produce syrups, particularly high fructose corn syrup, a sweetener; and also fermented and distilled to produce grain alcohol. Grain alcohol from maize is traditionally the source of Bourbon whiskey. Corn flour is used to make cornbread and other baked products.

 

In prehistoric times Mesoamerican women used a metate to process maize into ground cornmeal, allowing the preparation of foods that were more calorie dense than popcorn. After ceramic vessels were invented the Olmec people began to cook maize together with beans, improving the nutritional value of the staple meal. Although maize naturally contains niacin, an important nutrient, it was not bioavailable without the process of nixtamalization. The Maya used nixtamal meal to make varieties of porridges and tamales. The process was later used in the cuisine of the American South to prepare corn for grits and hominy.

 

Maize is a staple of Mexican cuisine. Masa (cornmeal treated with limewater) is the main ingredient for tortillas, atole and many other dishes of Central American food. It is the main ingredient of corn tortilla, tamales, pozole, atole and all the dishes based on them, like tacos, quesadillas, chilaquiles, enchiladas, tostadas and many more. In Mexico the fungus of maize, known as huitlacoche, is considered a delicacy.

 

Coarse maize meal is made into a thick porridge in many cultures: from the polenta of Italy, the angu of Brazil, the mămăligă of Romania, to cornmeal mush in the US (or hominy grits in the South) or the food called mieliepap in South Africa and sadza, nshima, ugali and other names in other parts of Africa. Introduced into Africa by the Portuguese in the 16th century, maize has become Africa's most important staple food crop. These are commonly eaten in the Southeastern United States, foods handed down from Native Americans, who called the dish sagamite.

 

Maize can also be harvested and consumed in the unripe state, when the kernels are fully grown but still soft. Unripe maize must usually be cooked to become palatable; this may be done by simply boiling or roasting the whole ears and eating the kernels right off the cob. Sweet corn, a genetic variety that is high in sugars and low in starch, is usually consumed in the unripe state. Such corn on the cob is a common dish in the United States, Canada, United Kingdom, Cyprus, some parts of South America, and the Balkans, but virtually unheard of in some European countries. Corn on the cob was hawked on the streets of early 19th-century New York City by poor, barefoot "Hot Corn Girls", who were thus the precursors of hot dog carts, churro wagons, and fruit stands seen on the streets of big cities today.

 

Within the United States, the usage of maize for human consumption constitutes only around 1/40th of the amount grown in the country. In the United States and Canada, maize is mostly grown to feed livestock, as forage, silage (made by fermentation of chopped green cornstalks), or grain. Maize meal is also a significant ingredient of some commercial animal food products.

 

NUTRITIONAL VALUE

Raw, yellow, sweet maize kernels are composed of 76% water, 19% carbohydrates, 3% protein, and 1% fat (table). In a 100-gram serving, maize kernels provide 86 calories and are a good source (10–19% of the Daily Value) of the B vitamins, thiamin, niacin (but see Pellagra warning below), pantothenic acid (B5) and folate (right table for raw, uncooked kernels, USDA Nutrient Database). In moderate amounts, they also supply dietary fiber and the essential minerals, magnesium and phosphorus whereas other nutrients are in low amounts (table).

 

Maize has suboptimal amounts of the essential amino acids tryptophan and lysine, which accounts for its lower status as a protein source. However, the proteins of beans and legumes complement those of maize.

 

FEED AND FODDER FOR LIVESTOCK

Maize is a major source of both grain feed and fodder for livestock. It is fed to the livestock in various ways. When it is used as a grain crop, the dried kernels are used as feed. They are often kept on the cob for storage in a corn crib, or they may be shelled off for storage in a grain bin. The farm that consumes the feed may produce it, purchase it on the market, or some of both. When the grain is used for feed, the rest of the plant (the corn stover) can be used later as fodder, bedding (litter), or soil amendment. When the whole maize plant (grain plus stalks and leaves) is used for fodder, it is usually chopped all at once and ensilaged, as digestibility and palatability are higher in the ensilaged form than in the dried form. Maize silage is one of the most valuable forages for ruminants. Before the advent of widespread ensilaging, it was traditional to gather the corn into shocks after harvesting, where it dried further. With or without a subsequent move to the cover of a barn, it was then stored for weeks to several months until fed to the livestock. Today ensilaging can occur not only in siloes but also in silage wrappers. However, in the tropics, maize can be harvested year-round and fed as green forage to the animals.

 

CHEMICALS

Starch from maize can also be made into plastics, fabrics, adhesives, and many other chemical products.

 

The corn steep liquor, a plentiful watery byproduct of maize wet milling process, is widely used in the biochemical industry and research as a culture medium to grow many kinds of microorganisms.

 

Chrysanthemin is found in purple corn and is used as a food coloring.

 

BIO-FUEL

"Feed maize" is being used increasingly for heating; specialized corn stoves (similar to wood stoves) are available and use either feed maize or wood pellets to generate heat. Maize cobs are also used as a biomass fuel source. Maize is relatively cheap and home-heating furnaces have been developed which use maize kernels as a fuel. They feature a large hopper that feeds the uniformly sized maize kernels (or wood pellets or cherry pits) into the fire.[citation needed]

 

Maize is increasingly used as a feedstock for the production of ethanol fuel.[120] When considering where to construct an ethanol plant, one of the site selection criteria is to ensure there is locally available feedstock. Ethanol is mixed with gasoline to decrease the amount of pollutants emitted when used to fuel motor vehicles. High fuel prices in mid-2007 led to higher demand for ethanol, which in turn led to higher prices paid to farmers for maize. This led to the 2007 harvest being one of the most profitable maize crops in modern history for farmers. Because of the relationship between fuel and maize, prices paid for the crop now tend to track the price of oil.

 

The price of food is affected to a certain degree by the use of maize for biofuel production. The cost of transportation, production, and marketing are a large portion (80%) of the price of food in the United States. Higher energy costs affect these costs, especially transportation. The increase in food prices the consumer has been seeing is mainly due to the higher energy cost. The effect of biofuel production on other food crop prices is indirect. Use of maize for biofuel production increases the demand, and therefore price of maize. This, in turn, results in farm acreage being diverted from other food crops to maize production. This reduces the supply of the other food crops and increases their prices.

 

Maize is widely used in Germany as a feedstock for biogas plants. Here the maize is harvested, shredded then placed in silage clamps from which it is fed into the biogas plants. This process makes use of the whole plant rather than simply using the kernels as in the production of fuel ethanol.

 

A biomass gasification power plant in Strem near Güssing, Burgenland, Austria, began in 2005. Research is being done to make diesel out of the biogas by the Fischer Tropsch method.

 

Increasingly, ethanol is being used at low concentrations (10% or less) as an additive in gasoline (gasohol) for motor fuels to increase the octane rating, lower pollutants, and reduce petroleum use (what is nowadays also known as "biofuels" and has been generating an intense debate regarding the human beings' necessity of new sources of energy, on the one hand, and the need to maintain, in regions such as Latin America, the food habits and culture which has been the essence of civilizations such as the one originated in Mesoamerica; the entry, January 2008, of maize among the commercial agreements of NAFTA has increased this debate, considering the bad labor conditions of workers in the fields, and mainly the fact that NAFTA "opened the doors to the import of maize from the United States, where the farmers who grow it receive multimillion-dollar subsidies and other government supports. ... According to OXFAM UK, after NAFTA went into effect, the price of maize in Mexico fell 70% between 1994 and 2001. The number of farm jobs dropped as well: from 8.1 million in 1993 to 6.8 million in 2002. Many of those who found themselves without work were small-scale maize growers."). However, introduction in the northern latitudes of the US of tropical maize for biofuels, and not for human or animal consumption, may potentially alleviate this.

 

COMMODITY

Maize is bought and sold by investors and price speculators as a tradable commodity using corn futures contracts. These "futures" are traded on the Chicago Board of Trade (CBOT) under ticker symbol C. They are delivered every year in March, May, July, September, and December.

Ornamental and other uses

 

Some forms of the plant are occasionally grown for ornamental use in the garden. For this purpose, variegated and colored leaf forms as well as those with colorful ears are used.

 

Corncobs can be hollowed out and treated to make inexpensive smoking pipes, first manufactured in the United States in 1869.

 

An unusual use for maize is to create a "corn maze" (or "maize maze") as a tourist attraction. The idea of a maize maze was introduced by the American Maze Company who created a maze in Pennsylvania in 1993. Traditional mazes are most commonly grown using yew hedges, but these take several years to mature. The rapid growth of a field of maize allows a maze to be laid out using GPS at the start of a growing season and for the maize to grow tall enough to obstruct a visitor's line of sight by the start of the summer. In Canada and the US, these are popular in many farming communities.

 

Maize kernels can be used in place of sand in a sandboxlike enclosure for children's play.

 

Stigmas from female maize flowers, popularly called corn silk, are sold as herbal supplements.

 

Maize is used as a fish bait, called "dough balls". It is particularly popular in Europe for coarse fishing.

 

Additionally, feed corn is sometimes used by hunters to bait animals such as deer or wild hogs.

 

UNITED STATES USAGE BREAKDOWN

The breakdown of usage of the 12.1-billion-bushel (307-million-tonne) 2008 US maize crop was as follows, according to the World Agricultural Supply and Demand Estimates Report by the USDA.In the US since 2009/2010, maize feedstock use for ethanol production has somewhat exceeded direct use for livestock feed; maize use for fuel ethanol was 5,130 million bushels (130 million tonnes) in the 2013/2014 marketing year.A fraction of the maize feedstock dry matter used for ethanol production is usefully recovered as DDGS (dried distillers grains with solubles). In the 2010/2011 marketing year, about 29.1 million tonnes of DDGS were fed to US livestock and poultry. Because starch utilization in fermentation for ethanol production leaves other grain constituents more concentrated in the residue, the feed value per kg of DDGS, with regard to ruminant-metabolizable energy and protein, exceeds that of the grain. Feed value for monogastric animals, such as swine and poultry, is somewhat lower than for ruminants.

 

HAZARDS

PELLAGRA

When maize was first introduced into farming systems other than those used by traditional native-American peoples, it was generally welcomed with enthusiasm for its productivity. However, a widespread problem of malnutrition soon arose wherever maize was introduced as a staple food. This was a mystery, since these types of malnutrition were not normally seen among the indigenous Americans, for whom maize was the principal staple food.

 

It was eventually discovered that the indigenous Americans had learned to soak maize in alkali — water (the process now known as nixtamalization) — made with ashes and lime (calcium oxide) since at least 1200–1500 BC by Mesoamericans. They did this to liberate the corn hulls, but (unbeknownst to natives or colonists) it coincidentally liberates the B-vitamin niacin, the lack of which was the underlying cause of the condition known as pellagra.

 

Maize was introduced into the diet of non-indigenous Americans without the necessary cultural knowledge acquired over thousands of years in the Americas. In the late 19th century, pellagra reached epidemic proportions in parts of the southern US, as medical researchers debated two theories for its origin: the deficiency theory (which was eventually shown to be true) said that pellagra was due to a deficiency of some nutrient, and the germ theory said that pellagra was caused by a germ transmitted by stable flies. A third theory, promoted by the eugenicist Charles Davenport, held that people only contracted pellagra if they were susceptible to it due to certain "constitutional, inheritable" traits of the affected individual.

 

Once alkali processing and dietary variety were understood and applied, pellagra disappeared in the developed world. The development of high lysine maize and the promotion of a more balanced diet have also contributed to its demise. Pellagra still exists today in food-poor areas and refugee camps where people survive on donated maize.

 

ALLERGY

Maize contains lipid transfer protein, an indigestible protein that survives cooking. This protein has been linked to a rare and understudied allergy to maize in humans. The allergic reaction can cause skin rash, swelling or itching of mucous membranes, diarrhea, vomiting, asthma and, in severe cases, anaphylaxis. It is unclear how common this allergy is in the general population.

 

MYCOTOXINS

Fungicide application does not reduce fungal growth or mycotoxin dramatically, although it can be a part of a successful reduction strategy. Among the most common toxins are those produced by Aspergillus and Fusarium spp. The most common toxins are aflatoxins, fumonisins, zearalenone, and ochratoxin A. Bt maize discourages insect vectors and by so doing it dramatically reduces concentrations of fumonisins, significantly reduces aflatoxins, but only mildly reduces others.

 

ART

Maize has been an essential crop in the Andes since the pre-Columbian era. The Moche culture from Northern Peru made ceramics from earth, water, and fire. This pottery was a sacred substance, formed in significant shapes and used to represent important themes. Maize was represented anthropomorphically as well as naturally.

 

In the United States, maize ears along with tobacco leaves are carved into the capitals of columns in the United States Capitol building. Maize itself is sometimes used for temporary architectural detailing when the intent is to celebrate the fall season, local agricultural productivity and culture. Bundles of dried maize stalks are often displayed along with pumpkins, gourds and straw in autumnal displays outside homes and businesses. A well-known example of architectural use is the Corn Palace in Mitchell, South Dakota, which uses cobs and ears of colored maize to implement a mural design that is recycled annually. Another well-known example is the Field of Corn sculpture in Dublin, Ohio, where hundreds of concrete ears of corn stand in a grassy field.

 

A maize stalk with two ripe ears is depicted on the reverse of the Croatian 1 lipa coin, minted since 1993.

 

WIKIPEDIA

Maize (/meɪz/ MAYZ; Zea mays subsp. mays, from Spanish: maíz after Taino: mahiz), also known as corn (North American and Australian English), is a cereal grain first domesticated by indigenous peoples in southern Mexico about 10,000 years ago. The leafy stalk of the plant produces pollen inflorescences and separate ovuliferous inflorescences called ears that yield kernels or seeds, which are fruits.

 

Maize has become a staple food in many parts of the world, with the total production of maize surpassing that of wheat or rice. In addition to being consumed directly by humans (often in the form of masa), maize is also used for corn ethanol, animal feed and other maize products, such as corn starch and corn syrup. The six major types of maize are dent corn, flint corn, pod corn, popcorn, flour corn, and sweet corn.[5] Sugar-rich varieties called sweet corn are usually grown for human consumption as kernels, while field corn varieties are used for animal feed, various corn-based human food uses (including grinding into cornmeal or masa, pressing into corn oil, and fermentation and distillation into alcoholic beverages like bourbon whiskey), and as chemical feedstocks. Maize is also used in making ethanol and other biofuels.

 

Maize is widely cultivated throughout the world, and a greater weight of maize is produced each year than any other grain. In 2014, total world production was 1.04 billion tonnes. Maize is the most widely grown grain crop throughout the Americas, with 361 million metric tons grown in the United States alone in 2014. Genetically modified maize made up 85% of the maize planted in the United States in 2009. Subsidies in the United States help to account for its high level of cultivation of maize and its position as the largest producer in the world.

 

HISTORY

PRE-COLUMBIAN DEVELOPMENT

Maize is a cultigen; human intervention is required for it to propagate. Whether or not the kernels fall off the cob on their own is a key piece of evidence used in archaeology to distinguish domesticated maize from its naturally-propagating teosinte ancestor. Genetic evidence can also be used to determine when various lineages split.

 

Most historians believe maize was domesticated in the Tehuacán Valley of Mexico. Recent research in the early 21st century has modified this view somewhat; scholars now indicate the adjacent Balsas River Valley of south-central Mexico as the center of domestication.

 

An influential 2002 study by Matsuoka et al. has demonstrated that, rather than the multiple independent domestications model, all maize arose from a single domestication in southern Mexico about 9,000 years ago. The study also demonstrated that the oldest surviving maize types are those of the Mexican highlands. Later, maize spread from this region over the Americas along two major paths. This is consistent with a model based on the archaeological record suggesting that maize diversified in the highlands of Mexico before spreading to the lowlands.

 

Archaeologist Dolores Piperno has said:

 

A large corpus of data indicates that [maize] was dispersed into lower Central America by 7600 BP [5600 BC] and had moved into the inter-Andean valleys of Colombia between 7000 and 6000 BP [5000–4000 BC].

— Dolores Piperno, The Origins of Plant Cultivation and Domestication in the New World Tropics: Patterns, Process, and New Developments

 

Since then, even earlier dates have been published.

 

According to a genetic study by Embrapa, corn cultivation was introduced in South America from Mexico, in two great waves: the first, more than 6000 years ago, spread through the Andes. Evidence of cultivation in Peru has been found dating to about 6700 years ago. The second wave, about 2000 years ago, through the lowlands of South America.

 

The earliest maize plants grew only small, 25-millimetre-long (1 in) corn cobs, and only one per plant. In Jackson Spielvogel's view, many centuries of artificial selection (rather than the current view that maize was exploited by interplanting with teosinte) by the indigenous people of the Americas resulted in the development of maize plants capable of growing several cobs per plant, which were usually several centimetres/inches long each. The Olmec and Maya cultivated maize in numerous varieties throughout Mesoamerica; they cooked, ground and processed it through nixtamalization. It was believed that beginning about 2500 BC, the crop spread through much of the Americas. Research of the 21st century has established even earlier dates. The region developed a trade network based on surplus and varieties of maize crops.

 

Mapuches of south-central Chile cultivated maize along with quinoa and potatoes in pre-Hispanic times; however, potato was the staple food of most Mapuches, "specially in the southern and coastal [Mapuche] territories where maize did not reach maturity". Before the expansion of the Inca Empire maize was traded and transported as far south as 40°19' S in Melinquina, Lácar Department. In that location maize remains were found inside pottery dated to 730 ± 80 BP and 920 ± 60 BP. Probably this maize was brought across the Andes from Chile. The presence of maize in Guaitecas Archipelago (43°55' S), the southernmost outpost of pre-Hispanic agriculture, is reported by early Spanish explorers. However the Spanish may have misidentified the plant.

 

COLUMBIAN EXCHANGE

After the arrival of Europeans in 1492, Spanish settlers consumed maize, and explorers and traders carried it back to Europe and introduced it to other countries. Spanish settlers far preferred wheat bread to maize, cassava, or potatoes. Maize flour could not be substituted for wheat for communion bread, since in Christian belief only wheat could undergo transubstantiation and be transformed into the body of Christ. Some Spaniards worried that by eating indigenous foods, which they did not consider nutritious, they would weaken and risk turning into Indians. "In the view of Europeans, it was the food they ate, even more than the environment in which they lived, that gave Amerindians and Spaniards both their distinctive physical characteristics and their characteristic personalities." Despite these worries, Spaniards did consume maize. Archeological evidence from Florida sites indicate they cultivated it as well.

 

Maize spread to the rest of the world because of its ability to grow in diverse climates. It was cultivated in Spain just a few decades after Columbus's voyages and then spread to Italy, West Africa and elsewhere. Widespread cultivation most likely began in southern Spain in 1525, after which it quickly spread to the rest of the Spanish Empire including its territories in Italy (and, from there, to other Italian states). Maize had many advantages over wheat and barley; it yielded two and a half times the food energy per unit cultivated area, could be harvested in successive years from the same plot of land, and grew in wildly varying altitudes and climates, from relatively dry regions with only 250 mm (10 in) of annual rainfall to damp regions with over 5,000 mm (200 in). By the 17th century it was a common peasant food in Southwestern Europe, including Portugal, Spain, southern France, and Italy. By the 18th century, it was the chief food of the southern French and Italian peasantry, especially in the form of polenta in Italy.

Names

 

The word maize derives from the Spanish form of the indigenous Taíno word for the plant, mahiz. It is known by other names around the world.

 

The word "corn" outside the US, Canada, Australia, and New Zealand refers to any cereal crop, its meaning understood to vary geographically to refer to the local staple. In the United States,[30] Canada, Australia, and New Zealand, corn primarily means maize; this usage started as a shortening of "Indian corn". "Indian corn" primarily means maize (the staple grain of indigenous Americans), but can refer more specifically to multicolored "flint corn" used for decoration.

 

In places outside the US, Canada, Australia, and New Zealand, corn often refers to maize in culinary contexts. The narrower meaning is usually indicated by some additional word, as in sweet corn, sweetcorn, corn on the cob, baby corn, the puffed confection known as popcorn and the breakfast cereal known as corn flakes.

 

In Southern Africa, maize is commonly called mielie (Afrikaans) or mealie (English), words derived from the Portuguese word for maize, milho.

 

Maize is preferred in formal, scientific, and international usage because it refers specifically to this one grain, unlike corn, which has a complex variety of meanings that vary by context and geographic region. Maize is used by agricultural bodies and research institutes such as the FAO and CSIRO. National agricultural and industry associations often include the word maize in their name even in English-speaking countries where the local, informal word is something other than maize; for example, the Maize Association of Australia, the Indian Maize Development Association, the Kenya Maize Consortium and Maize Breeders Network, the National Maize Association of Nigeria, the Zimbabwe Seed Maize Association.

 

STRUCTURE AND PHYSIOLOGY

The maize plant is often 3 m (10 ft) in height, though some natural strains can grow 13 m (43 ft). The stem is commonly composed of 20 internodes of 18 cm (7 in) length. The leaves arise from the nodes, alternately on opposite sides on the stalk. A leaf, which grows from each node, is generally 9 cm (3+1⁄2 in) in width and 120 cm (3 ft 11 in) in length.

 

Ears develop above a few of the leaves in the midsection of the plant, between the stem and leaf sheath, elongating by around 3 mm (1⁄8 in) per day, to a length of 18 cm (7 in) with 60 cm (24 in) being the maximum alleged in the subspecies. They are female inflorescences, tightly enveloped by several layers of ear leaves commonly called husks. Certain varieties of maize have been bred to produce many additional developed ears. These are the source of the "baby corn" used as a vegetable in Asian cuisine.

 

The apex of the stem ends in the tassel, an inflorescence of male flowers. When the tassel is mature and conditions are suitably warm and dry, anthers on the tassel dehisce and release pollen. Maize pollen is anemophilous (dispersed by wind), and because of its large settling velocity, most pollen falls within a few meters of the tassel.

 

Elongated stigmas, called silks, emerge from the whorl of husk leaves at the end of the ear. They are often pale yellow and 18 cm (7 in) in length, like tufts of hair in appearance. At the end of each is a carpel, which may develop into a "kernel" if fertilized by a pollen grain. The pericarp of the fruit is fused with the seed coat referred to as "caryopsis", typical of the grasses, and the entire kernel is often referred to as the "seed". The cob is close to a multiple fruit in structure, except that the individual fruits (the kernels) never fuse into a single mass. The grains are about the size of peas, and adhere in regular rows around a white, pithy substance, which forms the ear. The maximum size of kernels is reputedly 2.5 cm (1 in). An ear commonly holds 600 kernels. They are of various colors: blackish, bluish-gray, purple, green, red, white and yellow. When ground into flour, maize yields more flour with much less bran than wheat does. It lacks the protein gluten of wheat and, therefore, makes baked goods with poor rising capability. A genetic variant that accumulates more sugar and less starch in the ear is consumed as a vegetable and is called sweet corn. Young ears can be consumed raw, with the cob and silk, but as the plant matures (usually during the summer months), the cob becomes tougher and the silk dries to inedibility. By the end of the growing season, the kernels dry out and become difficult to chew without cooking them tender first in boiling water.

 

Planting density affects multiple aspects of maize. Modern farming techniques in developed countries usually rely on dense planting, which produces one ear per stalk. Stands of silage maize are yet denser,[citation needed] and achieve a lower percentage of ears and more plant matter.

 

Maize is a facultative short-day plant and flowers in a certain number of growing degree days > 10 °C (50 °F) in the environment to which it is adapted. The magnitude of the influence that long nights have on the number of days that must pass before maize flowers is genetically prescribed and regulated by the phytochrome system.

Photoperiodicity can be eccentric in tropical cultivars such that the long days characteristic of higher latitudes allow the plants to grow so tall that they do not have enough time to produce seed before being killed by frost. These attributes, however, may prove useful in using tropical maize for biofuels.

 

Immature maize shoots accumulate a powerful antibiotic substance, 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA). DIMBOA is a member of a group of hydroxamic acids (also known as benzoxazinoids) that serve as a natural defense against a wide range of pests, including insects, pathogenic fungi and bacteria. DIMBOA is also found in related grasses, particularly wheat. A maize mutant (bx) lacking DIMBOA is highly susceptible to attack by aphids and fungi. DIMBOA is also responsible for the relative resistance of immature maize to the European corn borer (family Crambidae). As maize matures, DIMBOA levels and resistance to the corn borer decline.

 

Because of its shallow roots, maize is susceptible to droughts, intolerant of nutrient-deficient soils, and prone to be uprooted by severe winds.

 

While yellow maizes derive their color from lutein and zeaxanthin, in red-colored maizes, the kernel coloration is due to anthocyanins and phlobaphenes. These latter substances are synthesized in the flavonoids synthetic pathway from polymerization of flavan-4-ols by the expression of maize pericarp color1 (p1) gene which encodes an R2R3 myb-like transcriptional activator of the A1 gene encoding for the dihydroflavonol 4-reductase (reducing dihydroflavonols into flavan-4-ols) while another gene (Suppressor of Pericarp Pigmentation 1 or SPP1) acts as a suppressor. The p1 gene encodes an Myb-homologous transcriptional activator of genes required for biosynthesis of red phlobaphene pigments, while the P1-wr allele specifies colorless kernel pericarp and red cobs, and unstable factor for orange1 (Ufo1) modifies P1-wr expression to confer pigmentation in kernel pericarp, as well as vegetative tissues, which normally do not accumulate significant amounts of phlobaphene pigments. The maize P gene encodes a Myb homolog that recognizes the sequence CCT/AACC, in sharp contrast with the C/TAACGG bound by vertebrate Myb proteins.

 

The ear leaf is the leaf most closely associated with a particular developing ear. This leaf and above contribute 70%[57] to 75% to 90% of grain fill. Therefore fungicide application is most important in that region in most disease environments.

 

ABNORMAL FLOWERS

Maize flowers may sometimes exhibit mutations that lead to the formation of female flowers in the tassel. These mutations, ts4 and Ts6, prohibit the development of the stamen while simultaneously promoting pistil development. This may cause inflorescences containing both male and female flowers, or hermaphrodite flowers.

 

GENETICS

Maize is an annual grass in the family Gramineae, which includes such plants as wheat, rye, barley, rice, sorghum, and sugarcane. There are two major species of the genus Zea (out of six total): Zea mays (maize) and Zea diploperennis, which is a perennial type of teosinte. The annual teosinte variety called Zea mays mexicana is the closest botanical relative to maize. It still grows in the wild as an annual in Mexico and Guatemala.

 

Many forms of maize are used for food, sometimes classified as various subspecies related to the amount of starch each has:

 

Flour corn: Zea mays var. amylacea

Popcorn: Zea mays var. everta

Dent corn : Zea mays var. indentata

Flint corn: Zea mays var. indurata

Sweet corn: Zea mays var. saccharata and Zea mays var. rugosa

Waxy corn: Zea mays var. ceratina

Amylomaize: Zea mays

Pod corn: Zea mays var. tunicata Larrañaga ex A. St. Hil.

Striped maize: Zea mays var. japonica

 

This system has been replaced (though not entirely displaced) over the last 60 years by multivariable classifications based on ever more data. Agronomic data were supplemented by botanical traits for a robust initial classification, then genetic, cytological, protein and DNA evidence was added. Now, the categories are forms (little used), races, racial complexes, and recently branches.

 

Maize is a diploid with 20 chromosomes (n=10). The combined length of the chromosomes is 1500 cM. Some of the maize chromosomes have what are known as "chromosomal knobs": highly repetitive heterochromatic domains that stain darkly. Individual knobs are polymorphic among strains of both maize and teosinte.

 

Barbara McClintock used these knob markers to validate her transposon theory of "jumping genes", for which she won the 1983 Nobel Prize in Physiology or Medicine. Maize is still an important model organism for genetics and developmental biology today.

 

The centromeres have two types of structural components, both of which are found only in the centromeres: Large arrays of CentC, a short satellite DNA; and a few of a family of retrotransposons. The B chromosome, unlike the others, contains an additional repeat which extends into neighboring areas of the chromosome. Centromeres can accidentally shrink during division and still function, although it is thought this will fail if it shrinks below a few hundred kilobase. Kinetochores contain RNA originating from centromeres. Centromere regions can become inactive, and can continue in that state if the chromosome still has another active one.

 

The Maize Genetics Cooperation Stock Center, funded by the USDA Agricultural Research Service and located in the Department of Crop Sciences at the University of Illinois at Urbana-Champaign, is a stock center of maize mutants. The total collection has nearly 80,000 samples. The bulk of the collection consists of several hundred named genes, plus additional gene combinations and other heritable variants. There are about 1000 chromosomal aberrations (e.g., translocations and inversions) and stocks with abnormal chromosome numbers (e.g., tetraploids). Genetic data describing the maize mutant stocks as well as myriad other data about maize genetics can be accessed at MaizeGDB, the Maize Genetics and Genomics Database.

 

In 2005, the US National Science Foundation (NSF), Department of Agriculture (USDA) and the Department of Energy (DOE) formed a consortium to sequence the B73 maize genome. The resulting DNA sequence data was deposited immediately into GenBank, a public repository for genome-sequence data. Sequences and genome annotations have also been made available throughout the project's lifetime at the project's official site.

 

Primary sequencing of the maize genome was completed in 2008. On November 20, 2009, the consortium published results of its sequencing effort in Science. The genome, 85% of which is composed of transposons, was found to contain 32,540 genes (By comparison, the human genome contains about 2.9 billion bases and 26,000 genes). Much of the maize genome has been duplicated and reshuffled by helitrons—group of rolling circle transposons.

 

In Z. mays and various other angiosperms the MADS-box motif is involved in floral development. Early study in several angiosperm models including Z. mays was the beginning of research into the molecular evolution of floral structure in general, as well as their role in nonflowering plants.

 

EVOLUTION

As with many plants and animals, Z. mays has a positive correlation between effective population size and the magnitude of selection pressure. Z. m. having an EPS of ~650,000, it clusters with others of about the same EPS, and has 79% of its amino acid sites under selection.

 

Recombination is a significant source of diversity in Z. mays. (Note that this finding supersedes previous studies which showed no such correlation.)

 

This recombination/diversity effect is seen throughout plants but is also found to not occur – or not as strongly – in regions of high gene density. This is likely the reason that domesticated Z. mays has not seen as much of an increase in diversity within areas of higher density as in regions of lower density, although there is more evidence in other plants.

 

Some lines of maize have undergone ancient polyploidy events, starting 11m years ago. Over that time ~72% of polyploid duplicated genes have been retained, which is higher than other plants with older polyploidy events. Thus maize may be due to lose more duplicate genes as time goes along, similar to the course followed by the genomes of other plants. If so - if gene loss has merely not occurred yet - that could explain the lack of observed positive selection and lower negative selection which are observed in otherwise similar plants, i.e. also naturally outcrossing and with similar effective population sizes.

 

Ploidy does not appear to influence EPS or magnitude of selection effect in maize.

 

BREEDING

Maize reproduces sexually each year. This randomly selects half the genes from a given plant to propagate to the next generation, meaning that desirable traits found in the crop (like high yield or good nutrition) can be lost in subsequent generations unless certain techniques are used.

 

Maize breeding in prehistory resulted in large plants producing large ears. Modern breeding began with individuals who selected highly productive varieties in their fields and then sold seed to other farmers. James L. Reid was one of the earliest and most successful developing Reid's Yellow Dent in the 1860s. These early efforts were based on mass selection. Later breeding efforts included ear to row selection (C. G. Hopkins c. 1896), hybrids made from selected inbred lines (G. H. Shull, 1909), and the highly successful double cross hybrids using four inbred lines (D. F. Jones c. 1918, 1922). University supported breeding programs were especially important in developing and introducing modern hybrids. By the 1930s, companies such as Pioneer devoted to production of hybrid maize had begun to influence long-term development. Internationally important seed banks such as the International Maize and Wheat Improvement Center (CIMMYT) and the US bank at the Maize Genetics Cooperation Stock Center University of Illinois at Urbana-Champaign maintain germplasm important for future crop development.

 

Since the 1940s the best strains of maize have been first-generation hybrids made from inbred strains that have been optimized for specific traits, such as yield, nutrition, drought, pest and disease tolerance. Both conventional cross-breeding and genetic modification have succeeded in increasing output and reducing the need for cropland, pesticides, water and fertilizer. There is conflicting evidence to support the hypothesis that maize yield potential has increased over the past few decades. This suggests that changes in yield potential are associated with leaf angle, lodging resistance, tolerance of high plant density, disease/pest tolerance, and other agronomic traits rather than increase of yield potential per individual plant.

 

Tropical landraces remain an important and underutilized source of resistance alleles for for disease and for herbivores. Notable discoveries of rare alleles for this purpose were made by Dao et al 2014 and Sood et al 2014.

 

GLOBAL PROGRAM

CIMMYT operates a conventional breeding program to provide optimized strains. The program began in the 1980s. Hybrid seeds are distributed in Africa by the Drought Tolerant Maize for Africa project.

 

GENETIC MODIFICATION

Genetically modified (GM) maize was one of the 26 GM crops grown commercially in 2016. The vast majority of this is Bt maize. Grown since 1997 in the United States and Canada, 92% of the US maize crop was genetically modified in 2016 and 33% of the worldwide maize crop was GM in 2016. As of 2011, Herbicide-tolerant maize varieties were grown in Argentina, Australia, Brazil, Canada, China, Colombia, El Salvador, the European Union, Honduras, Japan, Korea, Malaysia, Mexico, New Zealand, Philippines, the Russian Federation, Singapore, South Africa, Taiwan, Thailand, and the United States. Insect-resistant maize was grown in Argentina, Australia, Brazil, Canada, Chile, China, Colombia, Egypt, the European Union, Honduras, Japan, Korea, Malaysia, Mexico, New Zealand, Philippines, South Africa, Switzerland, Taiwan, the United States, and Uruguay.

 

In September 2000, up to $50 million worth of food products were recalled due to the presence of Starlink genetically modified corn, which had been approved only for animal consumption and had not been approved for human consumption, and was subsequently withdrawn from the market.

 

ORIGIN

Maize is the domesticated variant of teosinte. The two plants have dissimilar appearance, maize having a single tall stalk with multiple leaves and teosinte being a short, bushy plant. The difference between the two is largely controlled by differences in just two genes, called grassy tillers-1 (gt1, A0A317YEZ1) and teosinte branched-1 (tb1, Q93WI2).

 

Several theories had been proposed about the specific origin of maize in Mesoamerica:

 

It is a direct domestication of a Mexican annual teosinte, Zea mays ssp. parviglumis, native to the Balsas River valley in south-eastern Mexico, with up to 12% of its genetic material obtained from Zea mays ssp. mexicana through introgression.

It has been derived from hybridization between a small domesticated maize (a slightly changed form of a wild maize) and a teosinte of section Luxuriantes, either Z. luxurians or Z. diploperennis.

It has undergone two or more domestications either of a wild maize or of a teosinte. (The term "teosinte" describes all species and subspecies in the genus Zea, excluding Zea mays ssp. mays.)

It has evolved from a hybridization of Z. diploperennis by Tripsacum dactyloides.

 

In the late 1930s, Paul Mangelsdorf suggested that domesticated maize was the result of a hybridization event between an unknown wild maize and a species of Tripsacum, a related genus. This theory about the origin of maize has been refuted by modern genetic testing, which refutes Mangelsdorf's model and the fourth listed above. 

 

The teosinte origin theory was proposed by the Russian botanist Nikolai Ivanovich Vavilov in 1931 and the later American Nobel Prize-winner George Beadle in 1932.: 10  It is supported experimentally and by recent studies of the plants' genomes. Teosinte and maize can cross-breed and produce fertile offspring. A number of questions remain concerning the species, among them:

 

how the immense diversity of the species of sect. Zea originated,

how the tiny archaeological specimens of 3500–2700 BC could have been selected from a teosinte, and

how domestication could have proceeded without leaving remains of teosinte or maize with teosintoid traits earlier than the earliest known until recently, dating from ca. 1100 BC.

 

The domestication of maize is of particular interest to researchers—archaeologists, geneticists, ethnobotanists, geographers, etc. The process is thought by some to have started 7,500 to 12,000 years ago. Research from the 1950s to 1970s originally focused on the hypothesis that maize domestication occurred in the highlands between the states of Oaxaca and Jalisco, because the oldest archaeological remains of maize known at the time were found there.

Connection with 'parviglumis' subspecies

Genetic studies, published in 2004 by John Doebley, identified Zea mays ssp. parviglumis, native to the Balsas River valley in Mexico's southwestern highlands, and also known as Balsas teosinte, as being the crop wild relative that is genetically most similar to modern maize. This was confirmed by further studies, which refined this hypothesis somewhat. Archaeobotanical studies, published in 2009, point to the middle part of the Balsas River valley as the likely location of early domestication; this river is not very long, so these locations are not very distant. Stone milling tools with maize residue have been found in an 8,700 year old layer of deposits in a cave not far from Iguala, Guerrero.

 

Doebley was part of the team that first published, in 2002, that maize had been domesticated only once, about 9,000 years ago, and then spread throughout the Americas.

 

A primitive corn was being grown in southern Mexico, Central America, and northern South America 7,000 years ago. Archaeological remains of early maize ears, found at Guila Naquitz Cave in the Oaxaca Valley, date back roughly 6,250 years; the oldest ears from caves near Tehuacan, Puebla, 5,450 B.P.

 

Maize pollen dated to 7,300 B.P. from San Andres, Tabasco, on the Caribbean coast has also been recovered.

 

As maize was introduced to new cultures, new uses were developed and new varieties selected to better serve in those preparations. Maize was the staple food, or a major staple – along with squash, Andean region potato, quinoa, beans, and amaranth – of most pre-Columbian North American, Mesoamerican, South American, and Caribbean cultures. The Mesoamerican civilization, in particular, was deeply interrelated with maize. Its traditions and rituals involved all aspects of maize cultivation – from the planting to the food preparation. Maize formed the Mesoamerican people's identity.

 

It is unknown what precipitated its domestication, because the edible portion of the wild variety is too small, and hard to obtain, to be eaten directly, as each kernel is enclosed in a very hard bivalve shell.

 

In 1939, George Beadle demonstrated that the kernels of teosinte are readily "popped" for human consumption, like modern popcorn.[91] Some have argued it would have taken too many generations of selective breeding to produce large, compressed ears for efficient cultivation. However, studies of the hybrids readily made by intercrossing teosinte and modern maize suggest this objection is not well founded.

 

SPREADING TO THE NORTH

Around 4,500 ago, maize began to spread to the north; it was first cultivated in what is now the United States at several sites in New Mexico and Arizona, about 4,100 ago.

 

During the first millennium AD, maize cultivation spread more widely in the areas north. In particular, the large-scale adoption of maize agriculture and consumption in eastern North America took place about A.D. 900. Native Americans cleared large forest and grassland areas for the new crop.

 

In 2005, research by the USDA Forest Service suggested that the rise in maize cultivation 500 to 1,000 years ago in what is now the southeastern United States corresponded with a decline of freshwater mussels, which are very sensitive to environmental changes.

 

CULTIVATION

PLANTING

Because it is cold-intolerant, in the temperate zones maize must be planted in the spring. Its root system is generally shallow, so the plant is dependent on soil moisture. As a plant that uses C4 carbon fixation, maize is a considerably more water-efficient crop than plants that use C3 carbon fixation such as alfalfa and soybeans. Maize is most sensitive to drought at the time of silk emergence, when the flowers are ready for pollination. In the United States, a good harvest was traditionally predicted if the maize was "knee-high by the Fourth of July", although modern hybrids generally exceed this growth rate. Maize used for silage is harvested while the plant is green and the fruit immature. Sweet corn is harvested in the "milk stage", after pollination but before starch has formed, between late summer and early to mid-autumn. Field maize is left in the field until very late in the autumn to thoroughly dry the grain, and may, in fact, sometimes not be harvested until winter or even early spring. The importance of sufficient soil moisture is shown in many parts of Africa, where periodic drought regularly causes maize crop failure and consequent famine. Although it is grown mainly in wet, hot climates, it has been said to thrive in cold, hot, dry or wet conditions, meaning that it is an extremely versatile crop.

 

Maize was planted by the Native Americans in hills, in a complex system known to some as the Three Sisters. Maize provided support for beans, and the beans provided nitrogen derived from nitrogen-fixing rhizobia bacteria which live on the roots of beans and other legumes; and squashes provided ground cover to stop weeds and inhibit evaporation by providing shade over the soil. This method was replaced by single species hill planting where each hill 60–120 cm (2 ft 0 in–3 ft 11 in) apart was planted with three or four seeds, a method still used by home gardeners. A later technique was "checked maize", where hills were placed

 

1 m (40 in) apart in each direction, allowing cultivators to run through the field in two directions. In more arid lands, this was altered and seeds were planted in the bottom of 10–12 cm (4–4+1⁄2 in) deep furrows to collect water. Modern technique plants maize in rows which allows for cultivation while the plant is young, although the hill technique is still used in the maize fields of some Native American reservations. When maize is planted in rows, it also allows for planting of other crops between these rows to make more efficient use of land space.

 

In most regions today, maize grown in residential gardens is still often planted manually with a hoe, whereas maize grown commercially is no longer planted manually but rather is planted with a planter. In North America, fields are often planted in a two-crop rotation with a nitrogen-fixing crop, often alfalfa in cooler climates and soybeans in regions with longer summers. Sometimes a third crop, winter wheat, is added to the rotation.

 

Many of the maize varieties grown in the United States and Canada are hybrids. Often the varieties have been genetically modified to tolerate glyphosate or to provide protection against natural pests. Glyphosate is an herbicide which kills all plants except those with genetic tolerance. This genetic tolerance is very rarely found in nature.

 

In the midwestern United States, low-till or no-till farming techniques are usually used. In low-till, fields are covered once, maybe twice, with a tillage implement either ahead of crop planting or after the previous harvest. The fields are planted and fertilized. Weeds are controlled through the use of herbicides, and no cultivation tillage is done during the growing season. This technique reduces moisture evaporation from the soil, and thus provides more moisture for the crop. The technologies mentioned in the previous paragraph enable low-till and no-till farming. Weeds compete with the crop for moisture and nutrients, making them undesirable.

 

HARVESTING

Before the 20th century, all maize harvesting was by manual labour, by grazing, or by some combination of those. Whether the ears were hand-picked and the stover was grazed, or the whole plant was cut, gathered, and shocked, people and livestock did all the work. Between the 1890s and the 1970s, the technology of maize harvesting expanded greatly. Today, all such technologies, from entirely manual harvesting to entirely mechanized, are still in use to some degree, as appropriate to each farm's needs, although the thoroughly mechanized versions predominate, as they offer the lowest unit costs when scaled to large farm operations. For small farms, their unit cost can be too high, as their higher fixed cost cannot be amortized over as many units.[citation needed]

 

Before World War II, most maize in North America was harvested by hand. This involved a large number of workers and associated social events (husking or shucking bees). From the 1890s onward, some machinery became available to partially mechanize the processes, such as one- and two-row mechanical pickers (picking the ear, leaving the stover) and corn binders, which are reaper-binders designed specifically for maize (for example, Video on YouTube). The latter produce sheaves that can be shocked. By hand or mechanical picker, the entire ear is harvested, which then requires a separate operation of a maize sheller to remove the kernels from the ear. Whole ears of maize were often stored in corn cribs, and these whole ears are a sufficient form for some livestock feeding use. Today corn cribs with whole ears, and corn binders, are less common because most modern farms harvest the grain from the field with a combine and store it in bins. The combine with a corn head (with points and snap rolls instead of a reel) does not cut the stalk; it simply pulls the stalk down. The stalk continues downward and is crumpled into a mangled pile on the ground, where it usually is left to become organic matter for the soil. The ear of maize is too large to pass between slots in a plate as the snap rolls pull the stalk away, leaving only the ear and husk to enter the machinery. The combine separates the husk and the cob, keeping only the kernels.

When maize is a silage crop, the entire plant is usually chopped at once with a forage harvester (chopper) and ensiled in silos or polymer wrappers. Ensiling of sheaves cut by a corn binder was formerly common in some regions but has become uncommon. For storing grain in bins, the moisture of the grain must be sufficiently low to avoid spoiling. If the moisture content of the harvested grain is too high, grain dryers are used to reduce the moisture content by blowing heated air through the grain. This can require large amounts of energy in the form of combustible gases (propane or natural gas) and electricity to power the blowers.

 

PRODUCTION

Maize is widely cultivated throughout the world, and a greater weight of maize is produced each year than any other grain. In 2018, total world production was 1.15 billion tonnes, led by the United States with 34.2% of the total (table). China produced 22.4% of the global total.

 

UNITED STATES

In 2016, maize production was forecast to be over 380 million metric tons (15 billion bushels), an increase of 11% over 2014 American production. Based on conditions as of August 2016, the expected yield would be the highest ever for the United States. The area of harvested maize was forecast to be 35 million hectares (87 million acres), an increase of 7% over 2015. Maize is especially popular in Midwestern states such as Indiana, Iowa, and Illinois; in the latter, it was named the state's official grain in 2017.

 

STORAGE

Drying is vital to prevent or at least reduce mycotoxin contamination. Aspergillus and Fusarium spp. are the most common mycotoxin sources, but there are others. Altogether maize contaminants are so common, and this crop is so economically important, that maize mycotoxins are among the most important in agriculture in general.

 

USES

HUMAN FOOD

Maize and cornmeal (ground dried maize) constitute a staple food in many regions of the world. Maize is used to produce cornstarch, a common ingredient in home cooking and many industrialized food products. Maize starch can be hydrolyzed and enzymatically treated to produce syrups, particularly high fructose corn syrup, a sweetener; and also fermented and distilled to produce grain alcohol. Grain alcohol from maize is traditionally the source of Bourbon whiskey. Corn flour is used to make cornbread and other baked products.

 

In prehistoric times Mesoamerican women used a metate to process maize into ground cornmeal, allowing the preparation of foods that were more calorie dense than popcorn. After ceramic vessels were invented the Olmec people began to cook maize together with beans, improving the nutritional value of the staple meal. Although maize naturally contains niacin, an important nutrient, it was not bioavailable without the process of nixtamalization. The Maya used nixtamal meal to make varieties of porridges and tamales. The process was later used in the cuisine of the American South to prepare corn for grits and hominy.

 

Maize is a staple of Mexican cuisine. Masa (cornmeal treated with limewater) is the main ingredient for tortillas, atole and many other dishes of Central American food. It is the main ingredient of corn tortilla, tamales, pozole, atole and all the dishes based on them, like tacos, quesadillas, chilaquiles, enchiladas, tostadas and many more. In Mexico the fungus of maize, known as huitlacoche, is considered a delicacy.

 

Coarse maize meal is made into a thick porridge in many cultures: from the polenta of Italy, the angu of Brazil, the mămăligă of Romania, to cornmeal mush in the US (or hominy grits in the South) or the food called mieliepap in South Africa and sadza, nshima, ugali and other names in other parts of Africa. Introduced into Africa by the Portuguese in the 16th century, maize has become Africa's most important staple food crop. These are commonly eaten in the Southeastern United States, foods handed down from Native Americans, who called the dish sagamite.

 

Maize can also be harvested and consumed in the unripe state, when the kernels are fully grown but still soft. Unripe maize must usually be cooked to become palatable; this may be done by simply boiling or roasting the whole ears and eating the kernels right off the cob. Sweet corn, a genetic variety that is high in sugars and low in starch, is usually consumed in the unripe state. Such corn on the cob is a common dish in the United States, Canada, United Kingdom, Cyprus, some parts of South America, and the Balkans, but virtually unheard of in some European countries. Corn on the cob was hawked on the streets of early 19th-century New York City by poor, barefoot "Hot Corn Girls", who were thus the precursors of hot dog carts, churro wagons, and fruit stands seen on the streets of big cities today.

 

Within the United States, the usage of maize for human consumption constitutes only around 1/40th of the amount grown in the country. In the United States and Canada, maize is mostly grown to feed livestock, as forage, silage (made by fermentation of chopped green cornstalks), or grain. Maize meal is also a significant ingredient of some commercial animal food products.

 

NUTRITIONAL VALUE

Raw, yellow, sweet maize kernels are composed of 76% water, 19% carbohydrates, 3% protein, and 1% fat (table). In a 100-gram serving, maize kernels provide 86 calories and are a good source (10–19% of the Daily Value) of the B vitamins, thiamin, niacin (but see Pellagra warning below), pantothenic acid (B5) and folate (right table for raw, uncooked kernels, USDA Nutrient Database). In moderate amounts, they also supply dietary fiber and the essential minerals, magnesium and phosphorus whereas other nutrients are in low amounts (table).

 

Maize has suboptimal amounts of the essential amino acids tryptophan and lysine, which accounts for its lower status as a protein source. However, the proteins of beans and legumes complement those of maize.

 

FEED AND FODDER FOR LIVESTOCK

Maize is a major source of both grain feed and fodder for livestock. It is fed to the livestock in various ways. When it is used as a grain crop, the dried kernels are used as feed. They are often kept on the cob for storage in a corn crib, or they may be shelled off for storage in a grain bin. The farm that consumes the feed may produce it, purchase it on the market, or some of both. When the grain is used for feed, the rest of the plant (the corn stover) can be used later as fodder, bedding (litter), or soil amendment. When the whole maize plant (grain plus stalks and leaves) is used for fodder, it is usually chopped all at once and ensilaged, as digestibility and palatability are higher in the ensilaged form than in the dried form. Maize silage is one of the most valuable forages for ruminants. Before the advent of widespread ensilaging, it was traditional to gather the corn into shocks after harvesting, where it dried further. With or without a subsequent move to the cover of a barn, it was then stored for weeks to several months until fed to the livestock. Today ensilaging can occur not only in siloes but also in silage wrappers. However, in the tropics, maize can be harvested year-round and fed as green forage to the animals.

 

CHEMICALS

Starch from maize can also be made into plastics, fabrics, adhesives, and many other chemical products.

 

The corn steep liquor, a plentiful watery byproduct of maize wet milling process, is widely used in the biochemical industry and research as a culture medium to grow many kinds of microorganisms.

 

Chrysanthemin is found in purple corn and is used as a food coloring.

 

BIO-FUEL

"Feed maize" is being used increasingly for heating; specialized corn stoves (similar to wood stoves) are available and use either feed maize or wood pellets to generate heat. Maize cobs are also used as a biomass fuel source. Maize is relatively cheap and home-heating furnaces have been developed which use maize kernels as a fuel. They feature a large hopper that feeds the uniformly sized maize kernels (or wood pellets or cherry pits) into the fire.[citation needed]

 

Maize is increasingly used as a feedstock for the production of ethanol fuel.[120] When considering where to construct an ethanol plant, one of the site selection criteria is to ensure there is locally available feedstock. Ethanol is mixed with gasoline to decrease the amount of pollutants emitted when used to fuel motor vehicles. High fuel prices in mid-2007 led to higher demand for ethanol, which in turn led to higher prices paid to farmers for maize. This led to the 2007 harvest being one of the most profitable maize crops in modern history for farmers. Because of the relationship between fuel and maize, prices paid for the crop now tend to track the price of oil.

 

The price of food is affected to a certain degree by the use of maize for biofuel production. The cost of transportation, production, and marketing are a large portion (80%) of the price of food in the United States. Higher energy costs affect these costs, especially transportation. The increase in food prices the consumer has been seeing is mainly due to the higher energy cost. The effect of biofuel production on other food crop prices is indirect. Use of maize for biofuel production increases the demand, and therefore price of maize. This, in turn, results in farm acreage being diverted from other food crops to maize production. This reduces the supply of the other food crops and increases their prices.

 

Maize is widely used in Germany as a feedstock for biogas plants. Here the maize is harvested, shredded then placed in silage clamps from which it is fed into the biogas plants. This process makes use of the whole plant rather than simply using the kernels as in the production of fuel ethanol.

 

A biomass gasification power plant in Strem near Güssing, Burgenland, Austria, began in 2005. Research is being done to make diesel out of the biogas by the Fischer Tropsch method.

 

Increasingly, ethanol is being used at low concentrations (10% or less) as an additive in gasoline (gasohol) for motor fuels to increase the octane rating, lower pollutants, and reduce petroleum use (what is nowadays also known as "biofuels" and has been generating an intense debate regarding the human beings' necessity of new sources of energy, on the one hand, and the need to maintain, in regions such as Latin America, the food habits and culture which has been the essence of civilizations such as the one originated in Mesoamerica; the entry, January 2008, of maize among the commercial agreements of NAFTA has increased this debate, considering the bad labor conditions of workers in the fields, and mainly the fact that NAFTA "opened the doors to the import of maize from the United States, where the farmers who grow it receive multimillion-dollar subsidies and other government supports. ... According to OXFAM UK, after NAFTA went into effect, the price of maize in Mexico fell 70% between 1994 and 2001. The number of farm jobs dropped as well: from 8.1 million in 1993 to 6.8 million in 2002. Many of those who found themselves without work were small-scale maize growers."). However, introduction in the northern latitudes of the US of tropical maize for biofuels, and not for human or animal consumption, may potentially alleviate this.

 

COMMODITY

Maize is bought and sold by investors and price speculators as a tradable commodity using corn futures contracts. These "futures" are traded on the Chicago Board of Trade (CBOT) under ticker symbol C. They are delivered every year in March, May, July, September, and December.

Ornamental and other uses

 

Some forms of the plant are occasionally grown for ornamental use in the garden. For this purpose, variegated and colored leaf forms as well as those with colorful ears are used.

 

Corncobs can be hollowed out and treated to make inexpensive smoking pipes, first manufactured in the United States in 1869.

 

An unusual use for maize is to create a "corn maze" (or "maize maze") as a tourist attraction. The idea of a maize maze was introduced by the American Maze Company who created a maze in Pennsylvania in 1993. Traditional mazes are most commonly grown using yew hedges, but these take several years to mature. The rapid growth of a field of maize allows a maze to be laid out using GPS at the start of a growing season and for the maize to grow tall enough to obstruct a visitor's line of sight by the start of the summer. In Canada and the US, these are popular in many farming communities.

 

Maize kernels can be used in place of sand in a sandboxlike enclosure for children's play.

 

Stigmas from female maize flowers, popularly called corn silk, are sold as herbal supplements.

 

Maize is used as a fish bait, called "dough balls". It is particularly popular in Europe for coarse fishing.

 

Additionally, feed corn is sometimes used by hunters to bait animals such as deer or wild hogs.

 

UNITED STATES USAGE BREAKDOWN

The breakdown of usage of the 12.1-billion-bushel (307-million-tonne) 2008 US maize crop was as follows, according to the World Agricultural Supply and Demand Estimates Report by the USDA.In the US since 2009/2010, maize feedstock use for ethanol production has somewhat exceeded direct use for livestock feed; maize use for fuel ethanol was 5,130 million bushels (130 million tonnes) in the 2013/2014 marketing year.A fraction of the maize feedstock dry matter used for ethanol production is usefully recovered as DDGS (dried distillers grains with solubles). In the 2010/2011 marketing year, about 29.1 million tonnes of DDGS were fed to US livestock and poultry. Because starch utilization in fermentation for ethanol production leaves other grain constituents more concentrated in the residue, the feed value per kg of DDGS, with regard to ruminant-metabolizable energy and protein, exceeds that of the grain. Feed value for monogastric animals, such as swine and poultry, is somewhat lower than for ruminants.

 

HAZARDS

PELLAGRA

When maize was first introduced into farming systems other than those used by traditional native-American peoples, it was generally welcomed with enthusiasm for its productivity. However, a widespread problem of malnutrition soon arose wherever maize was introduced as a staple food. This was a mystery, since these types of malnutrition were not normally seen among the indigenous Americans, for whom maize was the principal staple food.

 

It was eventually discovered that the indigenous Americans had learned to soak maize in alkali — water (the process now known as nixtamalization) — made with ashes and lime (calcium oxide) since at least 1200–1500 BC by Mesoamericans. They did this to liberate the corn hulls, but (unbeknownst to natives or colonists) it coincidentally liberates the B-vitamin niacin, the lack of which was the underlying cause of the condition known as pellagra.

 

Maize was introduced into the diet of non-indigenous Americans without the necessary cultural knowledge acquired over thousands of years in the Americas. In the late 19th century, pellagra reached epidemic proportions in parts of the southern US, as medical researchers debated two theories for its origin: the deficiency theory (which was eventually shown to be true) said that pellagra was due to a deficiency of some nutrient, and the germ theory said that pellagra was caused by a germ transmitted by stable flies. A third theory, promoted by the eugenicist Charles Davenport, held that people only contracted pellagra if they were susceptible to it due to certain "constitutional, inheritable" traits of the affected individual.

 

Once alkali processing and dietary variety were understood and applied, pellagra disappeared in the developed world. The development of high lysine maize and the promotion of a more balanced diet have also contributed to its demise. Pellagra still exists today in food-poor areas and refugee camps where people survive on donated maize.

 

ALLERGY

Maize contains lipid transfer protein, an indigestible protein that survives cooking. This protein has been linked to a rare and understudied allergy to maize in humans. The allergic reaction can cause skin rash, swelling or itching of mucous membranes, diarrhea, vomiting, asthma and, in severe cases, anaphylaxis. It is unclear how common this allergy is in the general population.

 

MYCOTOXINS

Fungicide application does not reduce fungal growth or mycotoxin dramatically, although it can be a part of a successful reduction strategy. Among the most common toxins are those produced by Aspergillus and Fusarium spp. The most common toxins are aflatoxins, fumonisins, zearalenone, and ochratoxin A. Bt maize discourages insect vectors and by so doing it dramatically reduces concentrations of fumonisins, significantly reduces aflatoxins, but only mildly reduces others.

 

ART

Maize has been an essential crop in the Andes since the pre-Columbian era. The Moche culture from Northern Peru made ceramics from earth, water, and fire. This pottery was a sacred substance, formed in significant shapes and used to represent important themes. Maize was represented anthropomorphically as well as naturally.

 

In the United States, maize ears along with tobacco leaves are carved into the capitals of columns in the United States Capitol building. Maize itself is sometimes used for temporary architectural detailing when the intent is to celebrate the fall season, local agricultural productivity and culture. Bundles of dried maize stalks are often displayed along with pumpkins, gourds and straw in autumnal displays outside homes and businesses. A well-known example of architectural use is the Corn Palace in Mitchell, South Dakota, which uses cobs and ears of colored maize to implement a mural design that is recycled annually. Another well-known example is the Field of Corn sculpture in Dublin, Ohio, where hundreds of concrete ears of corn stand in a grassy field.

 

A maize stalk with two ripe ears is depicted on the reverse of the Croatian 1 lipa coin, minted since 1993.

 

WIKIPEDIA

We're in the same place as Part 3, on the eastern side of Old Ore Road, at about 1.5 road mi (2.4 km) north of its intersection with the paved park road to Rio Grande Village (Park Road 12). Looking eastward.

 

This is a close-up of the same community of plants shown in the previous image. And the emphasis here is really on the Candelilla (Euphorbia antisyphilitica) plants, with their erect, pale-gray stems.

 

Those stems are coated with an antidesiccant wax—hence their ghostly color—that in previous decades was harvested for various human uses.

 

Keep in mind that while many plant genera are pretty polymorphic, Euphorbia takes things to extremes. It also contains the arborescent and fancy-flowering Poinsettia (E. pulcherrima), tiny flat-growing herbs, the spiny Crown of Thorns (E. milii), and various succulents, tall or tubby, that are often mistaken for cacti.

 

Also present in the scene shown above is a supporting cast of yellowish-green Lechuguillas (Agave lechuguilla) and, in the background, what are probably Faxon Yuccas (Yucca faxoniana) and some species of Opuntia (Prickly Pear).

 

To see the other photos and descriptions in this set, visit my my Integrative Natural History of Old Ore Road album.

 

The Elbe Sandstone Mountains,[1] also called the Elbe sandstone highlands[2] (Czech: Labské pískovce; German: Elbsandsteingebirge) is a mountain range straddling the border between the state of Saxony in southeastern Germany and the North Bohemian region of the Czech Republic, with about three-quarters of the area lying on the German side. The mountains are also referred to as Saxon Switzerland and Bohemian Switzerland in both German and Czech (Sächsische Schweiz and Böhmische Schweiz in German, Saské Švýcarsko and České Švýcarsko in Czech) or simply combined as Saxon-Bohemian Switzerland.[3] In both countries, the mountain range has been declared a national park. The name derives from the sandstone which was carved by erosion. The river Elbe breaks through the mountain range in a steep and narrow valley.The Elbe Sandstone Mountains extend on both sides of the Elbe from the Saxon town of Pirna in the northwest toward Bohemian Děčín in the southeast. Their highest peak with 723 m (2,372 ft) is the Děčínský Sněžník in Bohemian Switzerland on the left bank of the river in Bohemian Switzerland north of Děčín. The mountain range links the Ore Mountains in the west with the Lusatian Highlands range of the Sudetes in the east. Saxon Switzerland and the Zittau Mountains of the Lusatian Mountains form the Saxon-Bohemian Chalk Sandstone Region.

     

The Elbe valley in Bohemian Switzerland. The mountains on the horizon lie in Saxony

[edit] Terrain

 

The most striking characteristic of this deeply dissected rocky mountain range is the extraordinary variety of terrain within the smallest area. Unique amongst the Central European Uplands are the constant changes between plains, ravines, table mountains and rocky regions with undeveloped areas of forest. This diversity is ecologically significant. The variety of different locations, each with its own conditions in terms of soil and microclimate, has produced an enormous richness of species. The numbers of ferns and mosses alone is unmatched by any other of the German central uplands.

 

The occurrence of Elbe sandstones and hence the Elbe Sandstone Mountains themselves is related to widespread deposition by a former sea in the Upper Cretaceous epoch. On the Saxon side of the border the term "Elbe Valley Cretaceous" (Elbtalkreide) is used, referring to a region stretching from Meißen-Oberau in the northwest through Dresden and Pirna into Saxon Switzerland, and which is formed by sandstones, planers and other rocks as well as basal conglomerates (Grundschottern or Basalkonglomerate) of older origin. Several erosion relics from Reinhardtsgrimma through Dippoldiswalde and the Tharandt Forest to Siebenlehn form isolated examples south of Dresden. They are mainly characterised by sandstones.

On the Bohemian side the sandstone beds continue and form part of the North Bohemian Cretaceous (Nordböhmische Kreide). The chalk sediments of the Zittau Basin are counted as part of the latter due to their regional-geological relationships. The sedimentary sequences of the Cretaceous sea continue across a wide area of the Czech Republic to Moravia. Together these beds form the Saxon-Bohemian Cretaceous Zone. In Czech geological circles, the Elbe Valley Cretaceous is described as the foothills of the Bohemian Cretaceous Basin[3] (Böhmischen Kreidebecken).

 

[edit] Geology

     

Hercules pillars in the Biela valley

The eroded sandstone landscape of this region was formed from depositions that accumulated on the bottom of the sea millions of years ago. Large rivers carried sand and other eroded debris into the Cretaceous sea. Rough quartz sand, clay and fine marl sank and became lithified layer by layer. A compact sandstone sequence developed, about 20 x 30 kilometres wide and up to 600 metres thick dating to the lower Cenomanian to Santonian stages.[3] The tremendous variety of shapes in the sandstone landscape is a result of the subsequent chemical and physical erosion and biological processes acting on the rocks formed from those sands laid down during the Cretaceous Period.

 

The inlets of a Cretaceous sea, together with marine currents, carried away sand over a very long period of time into a shallow zone of the sea and then the diagenetic processes at differing pressure regimes resulted in the formation of sandstone beds. Its stratification is characterized by variations in the horizontal structure (deposits of clay minerals, grain sizes of quartz, differences in the grain-cement) as well as a typical but fairly small fossil presence and variably porous strata.

 

After the Cretaceous sea had retreated (marine regression), the surface of the land was shaped by weathering influences and watercourses, of which the Elbe made the deepest incision. Later the Lusatian granodiorite was uplifted over the 600 metre thick sandstone slab along the Lusatian Fault and pushed it downwards until it fractured. This northern boundary of the sandstone deposit lies roughly along the line Pillnitz–Hohnstein–Hinterhermsdorf–Krásná Lípa (Schönlinde).

     

Crags near Rathen

In the Tertiary period, the adjacent region of the Central Bohemian Uplands and the Lusatian Mountains was shaped and affected by intense volcanism; but individual intrusions of magma also forced their way through the sandstone platform of the Elbe Sandstone Mountains. The most striking evidence of this phase in the earth's history are the conical basaltic hills of Růžovský vrch (Rosenberg), Cottaer Spitzberg and Raumberg, but also Großer and Kleiner Winterberg.

 

At its southwestern edge the sandstone plate was uplifted by over 200 metres at the Karsdorf Fault, whereby the slab was tilted even more and increased the gradient of the Elbe River. The water masses cut valleys into the rock with their streambeds and contributed in places to the formation of the rock faces. Over time the gradients reduced, the streambed of the Elbe widened out and changed its course time and again, partly as a result of the climatic influences of the ice ages.

 

The mineral composition of the sandstone beds has a direct effect on the morphology of the terrain. The fine-grained form with clayey-silty cement between the quartz grains causes banks and slopes with terracing. The beds of sandstone with siliceous cement are typically the basis of the formation of rock faces and crags. Small variations in the cement composition of the rock can have a visible impact on the landscape.[4]

 

Elbe Sandstone gets its characteristic cuboid appearance from its thick horizontal strata (massive bedding) and its vertical fissures. In 1839 Bernhard Cotta wrote about this in his comments on the geognostic map: "Vertical fissures and cracks cut through, often virtually at right angles, the horizontal layers and, as a result, parallelepiped bodies are formed, that have given rise to the description Quader Sandstone."[5]. Quader is German for an ashlar or block of stone, hence the name "Square Sandstone" is also used in English.[6]

 

The term quader sandstone mountains or square sandstone mountains (Quadersandsteingebirge), introduced by Hanns Bruno Geinitz in 1849, is an historic, geological term for similar sandstone deposits, but was also used in connexion with the Elbe Sandstone Mountains.[7][8].

     

Honeycomb weathering

The fissures were formed as a result of long-term tectonic stresses on the entire sandstone platform of the mountain range. This network of clefts runs through the sandstone beds in a relatively regular way, but in different directions in two regions of the range.[9] Subsequent weathering processes of very different forms and simultaneous complex deposition (leaching, frost and salt wedging, wind, solution weathering with sintering as well as biogenic and microbial effects) have further changed the nature of the rock surface. For example, collapse caves, small hole-like cavities (honeycomb weathering) with hourglass-shaped pillars (Sanduhr), chimneys, crevices and mighty, rugged rock faces.

  

Many morphological formations in the rocky landscape of the Elbe Sandstone Mountains are suspected to have been formed as a consequence of karstification. Important indicators of such processes in the polygenetic and polymorphic erosion landscape of the Elbe Sandstone Mountains are the furrows with parallel ridges between them (grykes and clints) that look like cart ruts and which are particularly common, as well as extensive cave systems. They are occasionally described by the term pseudokarst. The application of the concept to several erosion formations in the sandstone of this mountain range is however contentious.[10][11][12][13][14] Czech geologists have identified in quarzite-cemented sandstone areas in the northern part of the Bohemian Cretaceous Basin, karst features in the shape of spherical caverns and cave formations. According to them, these emerged as a result of solution processes by water in complex interactions with iron compounds from neighbouring or intrusive magmatic-volcanic rocks. The variation in relief in these sandstone regions is explained on the basis of these processes.[15][16] The Elbe Sandstone Mountains are the greatest cretaceous sandstone erosion complex in Europe.[17]

 

Human-induced changes caused by nearly 1,000 years of continual sandstone quarrying have also contributed in parts of the sandstone highlands to the appearance of the landscape today. The fissures (called Loose by the quarrymen) played an important role here, because they provided in effect natural divisions in the rock that were helpful when demolishing a rock face or when dressing the rough blocks of stone.[18]

 

The sandstone of this region is a sought-after building material used for example, for imposing city edifices such as the Church of Our Lady in Dresden.

  

Das Elbsandsteingebirge (tschechisch Labské pískovce bzw. Labské pískovcové pohoří) ist ein vorwiegend aus Sandstein aufgebautes Mittelgebirge am Oberlauf der Elbe in Sachsen (Deutschland) und Nordböhmen (Tschechien). Es ist etwa 700 km² groß und erreicht Höhen bis 723 Meter über dem Meeresspiegel. Der deutsche Teil wird im allgemeinen als Sächsische Schweiz, der tschechische als Böhmische Schweiz (České Švýcarsko) bezeichnet. Der heute häufiger gebrauchte Begriff „Sächsisch-Böhmische Schweiz“ (Českosaské Švýcarsko) ist davon abgeleitet.

  

Das Elbsandsteingebirge erstreckt sich beiderseits der Elbe zwischen der tschechischen Stadt Děčín (Tetschen-Bodenbach) und dem sächsischen Pirna. Die östliche Grenze befindet sich etwa entlang einer Linie zwischen Pirna, Hohnstein, Sebnitz, Chřibská, Česká Kamenice nach Děčín. Die westliche Begrenzung folgt von Pirna etwa dem Tal der Gottleuba zum Erzgebirgskamm und dann entlang des Jílovský potok (Eulaubach) nach Děčín. Der höchste Berg des Gebirges ist mit 723 Metern der Děčínský Sněžník (Hoher Schneeberg) im tschechischen Teil des Gebirges, die höchste deutsche Erhebung ist der Große Zschirnstein (561 m).

 

Im Elbsandsteingebirge befinden sich die Nationalparke Sächsische Schweiz und Böhmische Schweiz.

 

Allgemeines [Bearbeiten]

     

Basteibrücke bei Rathen

Das Charakteristische dieses stark zerklüfteten Felsengebirges ist sein außerordentlicher Formenreichtum auf engstem Raum. Einmalig unter den mitteleuropäischen Mittelgebirgen ist der ökologisch bedeutsame ständige Wechsel von Ebenen, Schluchten, Tafelbergen und Felsrevieren mit erhalten gebliebenen geschlossenen Waldbereichen. Die Vielfalt der unterschiedlichen Standorte mit jeweils eigenen Verhältnissen in Bezug auf Boden und Mikroklima haben eine enorme Artenvielfalt hervorgebracht. Allein die Vielfalt der vorkommenden Farne und Moose wird von keiner anderen deutschen Mittelgebirgslandschaft erreicht.

 

Das Auftreten des Elbsandsteins und damit des Elbsandsteingebirges steht im Zusammenhang mit den großräumigen Ablagerungen eines ehemaligen Meeres in der Oberkreide. Auf sächsischer Seite spricht man von der Elbtalkreide, die sich auf einem Gebiet zwischen Meißen-Oberau im Nordwesten über Dresden und Pirna bis in die Sächsische Schweiz erstreckt und in Form von Sandsteinen, Plänern und weiteren Gesteinen sowie an ihrer Basis mit Grundschottern (Basalkonglomerate) älterer Herkunft auftritt. Einige Erosionsrelikte zwischen Reinhardtsgrimma über Dippoldiswalde und Tharandter Wald bis Siebenlehn bilden südlich von Dresden isolierte Vorkommen. Sie sind hauptsächlich durch Sandsteine gekennzeichnet.

Auf böhmischer Seite setzten sich die Sandsteinablagerungen fort und stellen ein Teil der Nordböhmische Kreide dar. Die Kreidesedimente des Zittauer Beckens werden auf Grund ihrer regionalgeologischen Zusammenhänge der Nordböhmischen Kreide zugeordnet. Die Sedimentabfolgen aus dem Kreidemeer lassen sich in weiteren Landschaftsräumen Tschechiens bis nach Mähren verfolgen. Zusammen bilden diese Ablagerungen die Sächsisch-Böhmische Kreidezone. In der tschechischen Geologie wird die Elbtalkreide als ein Ausläufer des Böhmischen Kreidebeckens beschrieben.

 

Geologie [Bearbeiten]

     

Herkulessäulen im Bielatal

Der mannigfaltige Formenreichtum der Sandsteinlandschaft ist eine Folge chemisch-physikalischer Erosion und biologischer Prozesse von Gesteinen, die aus den in der Kreidezeit abgelagerten Sanden gebildet wurden.

 

Die Zuflüsse eines kreidezeitlichen Meeres und marine Strömungen transportierten über große Zeiträume hinweg in eine Flachmeerzone Sand, welcher über diagenetische Prozesse bei verschiedenen Druckregimen zur Ausbildung von Sandsteinschichten führte. Seine Schichtung ist durch wechselnde horizontale Strukturunterschiede (Einlagerungen von Tonmineralen, Korngrößen des Quarzes, Unterschiede in der Kornbindung) sowie eine typische aber überwiegend geringe Fossilführung sowie mehr oder weniger wasserführende Schichten charakterisiert.

 

Nachdem sich das kreidezeitliche Meer zurückgezogen (Regression) hatte, formten Verwitterungseinflüsse und Wasserläufe die Oberfläche, von denen die Elbe den stärksten Einschnitt erzeugte. Entlang der Lausitzer Verwerfung schob sich später im Norden der Lausitzer Granodiorit auf die etwa 600 Meter mächtige Sandsteinplatte und drückte diese nach unten, bis sie brach. Dieser Nordrand des Sandsteinvorkommens liegt ungefähr auf der Linie Pillnitz–Hohnstein–Hinterhermsdorf–Krásná Lípa (Schönlinde).

     

Wabenverwitterung

Im Tertiär wurde vor allem das angrenzende Gebiet des Böhmischen Mittelgebirges und des Lausitzer Gebirges durch einen intensiven Vulkanismus geformt und beeinflusst, einzelne Magmaintrusionen durchstießen aber auch die Sandsteintafel des Elbsandsteingebirges. Die markantesten Zeugnisse dieser erdgeschichtlichen Phase sind vor allem die basaltischen Kegelberge Růžovský vrch (Rosenberg), Cottaer Spitzberg und Raumberg, aber auch Großer und Kleiner Winterberg.

 

Am Südwestrand wurde die Sandsteinplatte an der Karsdorfer Störung um über 200 Meter angehoben, wodurch die Platte noch stärker kippte und sich das Gefälle des Elbestroms verstärkte. Die Wassermassen gruben mit ihrem Flussbett Täler in das Gestein und trugen stellenweise zur Bildung der Felswände bei. Mit der Zeit verminderte sich das Gefälle; das Flussbett des Elbestroms verbreiterte sich und wechselte immer wieder, auch durch eiszeitliche Klimaeinflüsse bedingt, seinen Verlauf.

 

Die mineralische Zusammensetzung der Sandsteinablagerungen hat unmittelbare Auswirkungen auf die Morphologie des Geländes. Der feinkörnige Typus mit tonig-schluffiger Bindung zwischen den Quarzkörnen verursacht Böschungen und Hänge mit Terrassierung. Die kieselig gebundenen Sandsteinbänke sind für die Ausbildung von Wänden und Klippen typisch. Geringe Schwankungen bei der Bindemittelzusammensetzung im Gestein können sich im Landschaftsbild sichtbar auswirken.[1]

 

Seine charakteristische Quader-Erscheinungsweise verdankt der Elbsandstein einer weitständigen horizontalen Schichtung (Bankung) und der vertikalen Zerklüftung. Bernhard Cotta schreibt 1839 in seinen Erläuterungen zur geognostischen Karte hierzu: „Verticale Klüfte und Spalten durchschneiden, unter sich ziemlich rechtwinkelig, die wagerechten Schichten, und dadurch entsteht jene Absonderung in parallelepipedische Körper, die zu dem Namen Quadersandstein Veranlassung gegeben hat.“[2]

 

Der Begriff Quadersandsteingebirge, von Hanns Bruno Geinitz 1849 eingeführt, ist ein historischer geologischer Terminus für vergleichbare Sandsteinablagerungen, wurde jedoch auch im Zusammenhang mit dem Elbsandsteingebirge verwendet.[3][4].

 

Die Klüfte bildeten sich durch lang anhaltende tektonische Beanspruchungen der gesamten Sandsteinplatte des Gebirges. Dieses Kluftnetz durchzieht, in zwei Bereichen des Gebirges mit unterschiedlichen Richtungen, in relativ regelmäßiger Form diese Sandsteinablagerungen.[5] Nachfolgend einsetzende Verwitterungsvorgänge sehr unterschiedlicher Art und gegenseitiger komplexer Überlagerung (Auswaschungen, Frost- und Salzsprengungen, Wind, Lösungsvorgänge mit Versinterungen sowie biogene und mikrobielle Einwirkungen) haben die Felsoberflächen weiter geprägt. Es entstanden beispielsweise Einsturzhöhlen, kleine lochähnliche Vertiefungen (Alveolen) mit Sanduhren, Kamine, Spalten und schroffe mächtige Wände.

Vielfältige morphologische Ausbildungen in der Felsenlandschaft des Elbsandsteingebirges werden hinsichtlich ihrer Entstehung als Folge einer Verkarstung diskutiert. Besonders häufig auftretende Furchen mit parallelen Kämmen, sie muten wie Karrenstrukturen an, sowie umfassende Höhlensysteme bieten in der polygenetischen und polymorphen Erosionslandschaft des Elbsandsteingebirges hierzu wichtige Anhaltspunkte. Sie werden gelegentlich mit dem Begriff Pseudokarst bezeichnet. Die Übertragung des Begriffs auf einige Erosionsformen im Sandstein des Elbsandsteingebirges und die daraus abgeleitete Erklärungsweise sind jedoch umstritten.[6][7][8][9][10] Tschechische Geologen konstatieren für quarzitisch gebundene Sandsteinbereiche im nördlichen Teil des Böhmischen Kreidebeckens Karsterscheinungen in Form von sphärischen Hohlräumen und Höhlenbildungen. Sie entstanden demnach durch Lösungsvorgänge von Wasser im komplexen Zusammenspiel mit Eisenverbindungen aus benachbarten bzw. intrudierten magmatisch-vulkanischen Gesteinen. Auf der Grundlage dieser Prozesse wird die Variantenvielfalt des Reliefs in jenen Sandsteingebieten erklärt.[11][12] Das Elbsandsteingebirge ist der größte Kreidesandsteinerosionskomplex in Europa.[13]

 

Die anthropogen verursachten Veränderungen durch den rund 1000 Jahre anhaltenden Sandsteinabbau trugen in Teilbereichen des Elbsandsteingebirges zusätzlich zur Formung des heute vorhandenen Landschaftsbildes bei. Dabei spielten die Klüfte (von den Steinbrechern Loose genannt) eine wichtige Rolle, da sie eine natürliche Begrenzung bei der Wandfällung und Rohblockzurichtung hilfreich vorgaben.[14]

  

More info and other languages available at:

 

de.wikipedia.org/wiki/Elbsandsteingebirge

The Elbe Sandstone Mountains,[1] also called the Elbe sandstone highlands[2] (Czech: Labské pískovce; German: Elbsandsteingebirge) is a mountain range straddling the border between the state of Saxony in southeastern Germany and the North Bohemian region of the Czech Republic, with about three-quarters of the area lying on the German side. The mountains are also referred to as Saxon Switzerland and Bohemian Switzerland in both German and Czech (Sächsische Schweiz and Böhmische Schweiz in German, Saské Švýcarsko and České Švýcarsko in Czech) or simply combined as Saxon-Bohemian Switzerland.[3] In both countries, the mountain range has been declared a national park. The name derives from the sandstone which was carved by erosion. The river Elbe breaks through the mountain range in a steep and narrow valley.The Elbe Sandstone Mountains extend on both sides of the Elbe from the Saxon town of Pirna in the northwest toward Bohemian Děčín in the southeast. Their highest peak with 723 m (2,372 ft) is the Děčínský Sněžník in Bohemian Switzerland on the left bank of the river in Bohemian Switzerland north of Děčín. The mountain range links the Ore Mountains in the west with the Lusatian Highlands range of the Sudetes in the east. Saxon Switzerland and the Zittau Mountains of the Lusatian Mountains form the Saxon-Bohemian Chalk Sandstone Region.

     

The Elbe valley in Bohemian Switzerland. The mountains on the horizon lie in Saxony

[edit] Terrain

 

The most striking characteristic of this deeply dissected rocky mountain range is the extraordinary variety of terrain within the smallest area. Unique amongst the Central European Uplands are the constant changes between plains, ravines, table mountains and rocky regions with undeveloped areas of forest. This diversity is ecologically significant. The variety of different locations, each with its own conditions in terms of soil and microclimate, has produced an enormous richness of species. The numbers of ferns and mosses alone is unmatched by any other of the German central uplands.

 

The occurrence of Elbe sandstones and hence the Elbe Sandstone Mountains themselves is related to widespread deposition by a former sea in the Upper Cretaceous epoch. On the Saxon side of the border the term "Elbe Valley Cretaceous" (Elbtalkreide) is used, referring to a region stretching from Meißen-Oberau in the northwest through Dresden and Pirna into Saxon Switzerland, and which is formed by sandstones, planers and other rocks as well as basal conglomerates (Grundschottern or Basalkonglomerate) of older origin. Several erosion relics from Reinhardtsgrimma through Dippoldiswalde and the Tharandt Forest to Siebenlehn form isolated examples south of Dresden. They are mainly characterised by sandstones.

On the Bohemian side the sandstone beds continue and form part of the North Bohemian Cretaceous (Nordböhmische Kreide). The chalk sediments of the Zittau Basin are counted as part of the latter due to their regional-geological relationships. The sedimentary sequences of the Cretaceous sea continue across a wide area of the Czech Republic to Moravia. Together these beds form the Saxon-Bohemian Cretaceous Zone. In Czech geological circles, the Elbe Valley Cretaceous is described as the foothills of the Bohemian Cretaceous Basin[3] (Böhmischen Kreidebecken).

 

[edit] Geology

     

Hercules pillars in the Biela valley

The eroded sandstone landscape of this region was formed from depositions that accumulated on the bottom of the sea millions of years ago. Large rivers carried sand and other eroded debris into the Cretaceous sea. Rough quartz sand, clay and fine marl sank and became lithified layer by layer. A compact sandstone sequence developed, about 20 x 30 kilometres wide and up to 600 metres thick dating to the lower Cenomanian to Santonian stages.[3] The tremendous variety of shapes in the sandstone landscape is a result of the subsequent chemical and physical erosion and biological processes acting on the rocks formed from those sands laid down during the Cretaceous Period.

 

The inlets of a Cretaceous sea, together with marine currents, carried away sand over a very long period of time into a shallow zone of the sea and then the diagenetic processes at differing pressure regimes resulted in the formation of sandstone beds. Its stratification is characterized by variations in the horizontal structure (deposits of clay minerals, grain sizes of quartz, differences in the grain-cement) as well as a typical but fairly small fossil presence and variably porous strata.

 

After the Cretaceous sea had retreated (marine regression), the surface of the land was shaped by weathering influences and watercourses, of which the Elbe made the deepest incision. Later the Lusatian granodiorite was uplifted over the 600 metre thick sandstone slab along the Lusatian Fault and pushed it downwards until it fractured. This northern boundary of the sandstone deposit lies roughly along the line Pillnitz–Hohnstein–Hinterhermsdorf–Krásná Lípa (Schönlinde).

     

Crags near Rathen

In the Tertiary period, the adjacent region of the Central Bohemian Uplands and the Lusatian Mountains was shaped and affected by intense volcanism; but individual intrusions of magma also forced their way through the sandstone platform of the Elbe Sandstone Mountains. The most striking evidence of this phase in the earth's history are the conical basaltic hills of Růžovský vrch (Rosenberg), Cottaer Spitzberg and Raumberg, but also Großer and Kleiner Winterberg.

 

At its southwestern edge the sandstone plate was uplifted by over 200 metres at the Karsdorf Fault, whereby the slab was tilted even more and increased the gradient of the Elbe River. The water masses cut valleys into the rock with their streambeds and contributed in places to the formation of the rock faces. Over time the gradients reduced, the streambed of the Elbe widened out and changed its course time and again, partly as a result of the climatic influences of the ice ages.

 

The mineral composition of the sandstone beds has a direct effect on the morphology of the terrain. The fine-grained form with clayey-silty cement between the quartz grains causes banks and slopes with terracing. The beds of sandstone with siliceous cement are typically the basis of the formation of rock faces and crags. Small variations in the cement composition of the rock can have a visible impact on the landscape.[4]

 

Elbe Sandstone gets its characteristic cuboid appearance from its thick horizontal strata (massive bedding) and its vertical fissures. In 1839 Bernhard Cotta wrote about this in his comments on the geognostic map: "Vertical fissures and cracks cut through, often virtually at right angles, the horizontal layers and, as a result, parallelepiped bodies are formed, that have given rise to the description Quader Sandstone."[5]. Quader is German for an ashlar or block of stone, hence the name "Square Sandstone" is also used in English.[6]

 

The term quader sandstone mountains or square sandstone mountains (Quadersandsteingebirge), introduced by Hanns Bruno Geinitz in 1849, is an historic, geological term for similar sandstone deposits, but was also used in connexion with the Elbe Sandstone Mountains.[7][8].

     

Honeycomb weathering

The fissures were formed as a result of long-term tectonic stresses on the entire sandstone platform of the mountain range. This network of clefts runs through the sandstone beds in a relatively regular way, but in different directions in two regions of the range.[9] Subsequent weathering processes of very different forms and simultaneous complex deposition (leaching, frost and salt wedging, wind, solution weathering with sintering as well as biogenic and microbial effects) have further changed the nature of the rock surface. For example, collapse caves, small hole-like cavities (honeycomb weathering) with hourglass-shaped pillars (Sanduhr), chimneys, crevices and mighty, rugged rock faces.

  

Many morphological formations in the rocky landscape of the Elbe Sandstone Mountains are suspected to have been formed as a consequence of karstification. Important indicators of such processes in the polygenetic and polymorphic erosion landscape of the Elbe Sandstone Mountains are the furrows with parallel ridges between them (grykes and clints) that look like cart ruts and which are particularly common, as well as extensive cave systems. They are occasionally described by the term pseudokarst. The application of the concept to several erosion formations in the sandstone of this mountain range is however contentious.[10][11][12][13][14] Czech geologists have identified in quarzite-cemented sandstone areas in the northern part of the Bohemian Cretaceous Basin, karst features in the shape of spherical caverns and cave formations. According to them, these emerged as a result of solution processes by water in complex interactions with iron compounds from neighbouring or intrusive magmatic-volcanic rocks. The variation in relief in these sandstone regions is explained on the basis of these processes.[15][16] The Elbe Sandstone Mountains are the greatest cretaceous sandstone erosion complex in Europe.[17]

 

Human-induced changes caused by nearly 1,000 years of continual sandstone quarrying have also contributed in parts of the sandstone highlands to the appearance of the landscape today. The fissures (called Loose by the quarrymen) played an important role here, because they provided in effect natural divisions in the rock that were helpful when demolishing a rock face or when dressing the rough blocks of stone.[18]

 

The sandstone of this region is a sought-after building material used for example, for imposing city edifices such as the Church of Our Lady in Dresden.

  

Das Elbsandsteingebirge (tschechisch Labské pískovce bzw. Labské pískovcové pohoří) ist ein vorwiegend aus Sandstein aufgebautes Mittelgebirge am Oberlauf der Elbe in Sachsen (Deutschland) und Nordböhmen (Tschechien). Es ist etwa 700 km² groß und erreicht Höhen bis 723 Meter über dem Meeresspiegel. Der deutsche Teil wird im allgemeinen als Sächsische Schweiz, der tschechische als Böhmische Schweiz (České Švýcarsko) bezeichnet. Der heute häufiger gebrauchte Begriff „Sächsisch-Böhmische Schweiz“ (Českosaské Švýcarsko) ist davon abgeleitet.

  

Das Elbsandsteingebirge erstreckt sich beiderseits der Elbe zwischen der tschechischen Stadt Děčín (Tetschen-Bodenbach) und dem sächsischen Pirna. Die östliche Grenze befindet sich etwa entlang einer Linie zwischen Pirna, Hohnstein, Sebnitz, Chřibská, Česká Kamenice nach Děčín. Die westliche Begrenzung folgt von Pirna etwa dem Tal der Gottleuba zum Erzgebirgskamm und dann entlang des Jílovský potok (Eulaubach) nach Děčín. Der höchste Berg des Gebirges ist mit 723 Metern der Děčínský Sněžník (Hoher Schneeberg) im tschechischen Teil des Gebirges, die höchste deutsche Erhebung ist der Große Zschirnstein (561 m).

 

Im Elbsandsteingebirge befinden sich die Nationalparke Sächsische Schweiz und Böhmische Schweiz.

 

Allgemeines [Bearbeiten]

     

Basteibrücke bei Rathen

Das Charakteristische dieses stark zerklüfteten Felsengebirges ist sein außerordentlicher Formenreichtum auf engstem Raum. Einmalig unter den mitteleuropäischen Mittelgebirgen ist der ökologisch bedeutsame ständige Wechsel von Ebenen, Schluchten, Tafelbergen und Felsrevieren mit erhalten gebliebenen geschlossenen Waldbereichen. Die Vielfalt der unterschiedlichen Standorte mit jeweils eigenen Verhältnissen in Bezug auf Boden und Mikroklima haben eine enorme Artenvielfalt hervorgebracht. Allein die Vielfalt der vorkommenden Farne und Moose wird von keiner anderen deutschen Mittelgebirgslandschaft erreicht.

 

Das Auftreten des Elbsandsteins und damit des Elbsandsteingebirges steht im Zusammenhang mit den großräumigen Ablagerungen eines ehemaligen Meeres in der Oberkreide. Auf sächsischer Seite spricht man von der Elbtalkreide, die sich auf einem Gebiet zwischen Meißen-Oberau im Nordwesten über Dresden und Pirna bis in die Sächsische Schweiz erstreckt und in Form von Sandsteinen, Plänern und weiteren Gesteinen sowie an ihrer Basis mit Grundschottern (Basalkonglomerate) älterer Herkunft auftritt. Einige Erosionsrelikte zwischen Reinhardtsgrimma über Dippoldiswalde und Tharandter Wald bis Siebenlehn bilden südlich von Dresden isolierte Vorkommen. Sie sind hauptsächlich durch Sandsteine gekennzeichnet.

Auf böhmischer Seite setzten sich die Sandsteinablagerungen fort und stellen ein Teil der Nordböhmische Kreide dar. Die Kreidesedimente des Zittauer Beckens werden auf Grund ihrer regionalgeologischen Zusammenhänge der Nordböhmischen Kreide zugeordnet. Die Sedimentabfolgen aus dem Kreidemeer lassen sich in weiteren Landschaftsräumen Tschechiens bis nach Mähren verfolgen. Zusammen bilden diese Ablagerungen die Sächsisch-Böhmische Kreidezone. In der tschechischen Geologie wird die Elbtalkreide als ein Ausläufer des Böhmischen Kreidebeckens beschrieben.

 

Geologie [Bearbeiten]

     

Herkulessäulen im Bielatal

Der mannigfaltige Formenreichtum der Sandsteinlandschaft ist eine Folge chemisch-physikalischer Erosion und biologischer Prozesse von Gesteinen, die aus den in der Kreidezeit abgelagerten Sanden gebildet wurden.

 

Die Zuflüsse eines kreidezeitlichen Meeres und marine Strömungen transportierten über große Zeiträume hinweg in eine Flachmeerzone Sand, welcher über diagenetische Prozesse bei verschiedenen Druckregimen zur Ausbildung von Sandsteinschichten führte. Seine Schichtung ist durch wechselnde horizontale Strukturunterschiede (Einlagerungen von Tonmineralen, Korngrößen des Quarzes, Unterschiede in der Kornbindung) sowie eine typische aber überwiegend geringe Fossilführung sowie mehr oder weniger wasserführende Schichten charakterisiert.

 

Nachdem sich das kreidezeitliche Meer zurückgezogen (Regression) hatte, formten Verwitterungseinflüsse und Wasserläufe die Oberfläche, von denen die Elbe den stärksten Einschnitt erzeugte. Entlang der Lausitzer Verwerfung schob sich später im Norden der Lausitzer Granodiorit auf die etwa 600 Meter mächtige Sandsteinplatte und drückte diese nach unten, bis sie brach. Dieser Nordrand des Sandsteinvorkommens liegt ungefähr auf der Linie Pillnitz–Hohnstein–Hinterhermsdorf–Krásná Lípa (Schönlinde).

     

Wabenverwitterung

Im Tertiär wurde vor allem das angrenzende Gebiet des Böhmischen Mittelgebirges und des Lausitzer Gebirges durch einen intensiven Vulkanismus geformt und beeinflusst, einzelne Magmaintrusionen durchstießen aber auch die Sandsteintafel des Elbsandsteingebirges. Die markantesten Zeugnisse dieser erdgeschichtlichen Phase sind vor allem die basaltischen Kegelberge Růžovský vrch (Rosenberg), Cottaer Spitzberg und Raumberg, aber auch Großer und Kleiner Winterberg.

 

Am Südwestrand wurde die Sandsteinplatte an der Karsdorfer Störung um über 200 Meter angehoben, wodurch die Platte noch stärker kippte und sich das Gefälle des Elbestroms verstärkte. Die Wassermassen gruben mit ihrem Flussbett Täler in das Gestein und trugen stellenweise zur Bildung der Felswände bei. Mit der Zeit verminderte sich das Gefälle; das Flussbett des Elbestroms verbreiterte sich und wechselte immer wieder, auch durch eiszeitliche Klimaeinflüsse bedingt, seinen Verlauf.

 

Die mineralische Zusammensetzung der Sandsteinablagerungen hat unmittelbare Auswirkungen auf die Morphologie des Geländes. Der feinkörnige Typus mit tonig-schluffiger Bindung zwischen den Quarzkörnen verursacht Böschungen und Hänge mit Terrassierung. Die kieselig gebundenen Sandsteinbänke sind für die Ausbildung von Wänden und Klippen typisch. Geringe Schwankungen bei der Bindemittelzusammensetzung im Gestein können sich im Landschaftsbild sichtbar auswirken.[1]

 

Seine charakteristische Quader-Erscheinungsweise verdankt der Elbsandstein einer weitständigen horizontalen Schichtung (Bankung) und der vertikalen Zerklüftung. Bernhard Cotta schreibt 1839 in seinen Erläuterungen zur geognostischen Karte hierzu: „Verticale Klüfte und Spalten durchschneiden, unter sich ziemlich rechtwinkelig, die wagerechten Schichten, und dadurch entsteht jene Absonderung in parallelepipedische Körper, die zu dem Namen Quadersandstein Veranlassung gegeben hat.“[2]

 

Der Begriff Quadersandsteingebirge, von Hanns Bruno Geinitz 1849 eingeführt, ist ein historischer geologischer Terminus für vergleichbare Sandsteinablagerungen, wurde jedoch auch im Zusammenhang mit dem Elbsandsteingebirge verwendet.[3][4].

 

Die Klüfte bildeten sich durch lang anhaltende tektonische Beanspruchungen der gesamten Sandsteinplatte des Gebirges. Dieses Kluftnetz durchzieht, in zwei Bereichen des Gebirges mit unterschiedlichen Richtungen, in relativ regelmäßiger Form diese Sandsteinablagerungen.[5] Nachfolgend einsetzende Verwitterungsvorgänge sehr unterschiedlicher Art und gegenseitiger komplexer Überlagerung (Auswaschungen, Frost- und Salzsprengungen, Wind, Lösungsvorgänge mit Versinterungen sowie biogene und mikrobielle Einwirkungen) haben die Felsoberflächen weiter geprägt. Es entstanden beispielsweise Einsturzhöhlen, kleine lochähnliche Vertiefungen (Alveolen) mit Sanduhren, Kamine, Spalten und schroffe mächtige Wände.

Vielfältige morphologische Ausbildungen in der Felsenlandschaft des Elbsandsteingebirges werden hinsichtlich ihrer Entstehung als Folge einer Verkarstung diskutiert. Besonders häufig auftretende Furchen mit parallelen Kämmen, sie muten wie Karrenstrukturen an, sowie umfassende Höhlensysteme bieten in der polygenetischen und polymorphen Erosionslandschaft des Elbsandsteingebirges hierzu wichtige Anhaltspunkte. Sie werden gelegentlich mit dem Begriff Pseudokarst bezeichnet. Die Übertragung des Begriffs auf einige Erosionsformen im Sandstein des Elbsandsteingebirges und die daraus abgeleitete Erklärungsweise sind jedoch umstritten.[6][7][8][9][10] Tschechische Geologen konstatieren für quarzitisch gebundene Sandsteinbereiche im nördlichen Teil des Böhmischen Kreidebeckens Karsterscheinungen in Form von sphärischen Hohlräumen und Höhlenbildungen. Sie entstanden demnach durch Lösungsvorgänge von Wasser im komplexen Zusammenspiel mit Eisenverbindungen aus benachbarten bzw. intrudierten magmatisch-vulkanischen Gesteinen. Auf der Grundlage dieser Prozesse wird die Variantenvielfalt des Reliefs in jenen Sandsteingebieten erklärt.[11][12] Das Elbsandsteingebirge ist der größte Kreidesandsteinerosionskomplex in Europa.[13]

 

Die anthropogen verursachten Veränderungen durch den rund 1000 Jahre anhaltenden Sandsteinabbau trugen in Teilbereichen des Elbsandsteingebirges zusätzlich zur Formung des heute vorhandenen Landschaftsbildes bei. Dabei spielten die Klüfte (von den Steinbrechern Loose genannt) eine wichtige Rolle, da sie eine natürliche Begrenzung bei der Wandfällung und Rohblockzurichtung hilfreich vorgaben.[14]

  

More info and other languages available at:

 

de.wikipedia.org/wiki/Elbsandsteingebirge

The Danaid Eggfly (Hypolimnas misippus) is a widespread species of nymphalid butterfly. It is well known for polymorphism and mimicry.

 

Female - Polymorphic.

Female form inaria

 

First form : Upperside rich tawny. Fore wing : the costa, the apical half of the wing and the termen black, the inner margin of this black area follows a line crossing the cell obliquely and curving round to near apex of interspace 1 a ; a white spot beyond apex of cell; an oblique band of elongate white spots, a more transverse short subapical series of three or four much smaller white spots, and an inner and an outer sub-terminal transverse series of very small slender white lunules. Hind wing: a transverse round spot in interspace 7, the terminal margin broadly black, the latter traversed by two transverse series of paired small white lunules. Cilia of fore and hind wings white alternated with black. Underside paler tawny yellow, the disc of the fore wing deeper tawny; the markings are much as on the upperside but differ as follows :—Fore wing: three white spots along the anterior margin of cell, the black on the apical area beyond the oblique band of white spots replaced by golden. Hind wing: a black spot at base of vein 8, another at base of interspace 5, and a postdiscal transverse series of small white spots in addition to the markings as on the upperside.

 

Second form. Similar to the above but the disc of the hind wing on both upper and under sides white, =alcippoides, Butler.

 

Third form. Similar to the first form, but on the fore wing the oblique series of: elongate spots yellowish and tho middle portion of the black apical area tawny

 

This female butterfly mimics the Plain Tiger . Because of the poisonous taste of Plain Tiger, the predators will not eat Plain tiger . Since she looks like Plain Tiger, predators will not eat her .

 

Female polymorphism: Females of Hypolimnas misippus show a remarkable polymorphism whereas the males are monomorphic. All four female morphs are mimics of morphs of Danaus chrysippus, and genetics of female forms, male preferences and survival capabilities have been studied in Africa (review in D.A.S. Smith, in The Biology of Butterflies, 1984, R.I. Vane-Wright & P.R. Ackery eds, Academic Press, London). Two female forms only occur in tropical America, f. misippus and f. inaria (Cramer), the latter being very rare according to Riley. In Guadeloupe, f. inaria seems to be not so rare (the ratio misippus/inaria is 4/1 in Africa).

 

The male looks like THIS . I will upload a clear picture of the Male , soon.

Asian Paradise-flycatcher (Terpsiphone paradisi) - Female

 

(T. p. incei (Gould, 1852) breeds in eastern, northeastern and central China, in the Russian Far East and in the north of Korea; populations occurring in Southeast Asia are non-breeding.)

  

The Asian paradise flycatcher (Terpsiphone paradisi) is a medium-sized passerine bird native to Asia. Males have elongated central tail feathers, and in some populations a black and rufous plumage while others have white plumage. Females are short-tailed with rufous wings and a black head. They feed on insects, which they capture in the air often below a densely canopied tree.

 

With an extremely large range and a large population that appears to be stable, they have been evaluated as Least Concern by IUCN since 2004.

 

In his first description of 1758, Carl von Linné nominated the species Corvus paradisi. Paradise-flycatchers used to be classified with the Old World flycatcher family Muscicapidae, but are now placed in the family Monarchidae together with monarch flycatchers.

  

Characteristics

 

Adult Asian paradise flycatchers are 19–22 cm (7.5–8.7 in) long. Their heads are glossy black with a black crown and crest, their black bill round and sturdy, their eyes black. Female are rufous on the back with a greyish throat and underparts. Their wings are 86–92 mm (3.4–3.6 in) long. Young males look very much like females but have a black throat and blue-ringed eyes. As adults they develop up to 24 cm (9.4 in) long tail feathers with two central tail feathers growing up to 30 cm (12 in) long drooping streamers.

Young males are rufous and have short tails. They acquire long tails in their second or third year. Adult males are either predominantly bright rufous above or predominantly white. Some specimens show some degree of intermediacy between rufous and white. Long-tailed rufous birds are generally devoid of shaft streaks on the wing and tail feathers, while in white birds the shaft streaks, and sometimes the edges of the wing and tail feathers are black.

 

In the early 1960s, 680 long-tailed males were examined that are contained in collections of the British Museum of Natural History, Chicago Natural History Museum, Peabody Museum, Carnegie Museum, American Museum of Natural History, United States National Museum and Royal Ontario Museum. The specimens came from almost the entire range of the species, though some areas were poorly represented. The relative frequency of the rufous and white plumage types varies geographically. Rufous birds are rare in the extreme southeastern part of the species' range. Throughout the Indian area and, to a lesser extent, in China, asymmetrically patterned intermediates occur. Intermediates are rare or absent throughout the rest of the range of the species. In general, long-tailed males are:

 

- predominantly rufous with some white in wings and tail — collected in Turkestan, Kashmir, northern India, Punjab, Maharashtra, Sikkim and in Sri Lanka;

 

- predominantly rufous with some white in wings — collected in Iran, Afghanistan, Baluchistan, Punjab, Kashmir, northern and central India, Rajasthan, Maharashtra, Bihar, Nepal;

 

- predominantly rufous with some white in tail — collected in Punjab, northern and central India, Kolkata, Sri Lanka and in the Upper Yangtse Valley in China;

 

- predominantly white with some rufous in tail and wings — collected in Kashmir, Maharashtra, Sichuan and North China;

 

- predominantly white with some rufous in tail — collected in Maharashtra and Fuzhou, China;

 

- predominantly white with back partly rufous — collected in Punjab and Chennai;

 

- predominantly white with wings and tail irregularly blotched and washed with rufous in places — in the extreme southeastern edge of the range of the species : Alor Island and Sumba;

 

- moulting from rufous into white plumage — collected in North Bihar.

  

Possible interpretations of this phenomenon are : males may be polymorphic for rufous and white plumage colour; rufous birds may be sub-adults; and there may even be two sympatric species distinguishable only in the male.

  

Habitat and distribution

 

Asian paradise flycatchers inhabit thick forests and well-wooded habitats from Turkestan to Manchuria, all over India and Sri Lanka to the Malay Archipelago on the islands of Sumba and Alor. They are vagrant in Korea and Maldives, and regionally extinct in Singapore.

 

They are migratory and spend the winter season in tropical Asia. There are resident populations in southern India and Sri Lanka, hence both visiting migrants and the locally breeding subspecies occur in these areas in winter.

 

According to Linné’s first description Asian paradise flycatchers were only distributed in India. Later ornithologists observed this spectacular bird in other Asian countries, and based on differences in plumage of males described several subspecies, of which the following 14 are recognized today:

 

- T. p. paradisi (Linnaeus, 1758) breeds in central and southern India, central Bangladesh and south-western Myanmar; populations occurring in Sri Lanka in the winter season are non-breeding.

 

- T. p. leucogaster (Swainson, 1838) breeds in the western Tian Shan, in Afghanistan, in the north of Pakistan, in northwestern and central India, in Nepal’s western and central regions; populations occurring in the east of Pakistan and in the south of India migrate towards the foothills of the Himalayas in spring for breeding.

 

- T. p. affinis (Blyth, 1846) inhabits Malaysia and Sumatra.

 

- T. p. incei (Gould, 1852) breeds in eastern, northeastern and central China, in the Russian Far East and in the north of Korea; populations occurring in Southeast Asia are non-breeding.

 

- T. p. insularis (Salvadori, 1887) inhabits the island Nias off the western coast of Sumatra.

 

- T. p. nicobarica (Oates, 1890) inhabits the Nicobar Islands.

 

- T. p. sumbaensis (Meyer, 1894) inhabits the Lesser Sunda Island Sumba.

 

- T. p. floris (Büttikofer, 1894) inhabits the Lesser Sunda Islands Sumbawa, Flores, Lomblen and Alor Island.

 

- T. p. procera (Richmond, 1903) inhabits the island Simeuluë northwest off the coast of Sumatra.

 

- T. p. ceylonensis (Zarudny & Harms, 1912) inhabits Sri Lanka.

 

- T. p. borneensis (Hartert, 1916) inhabits Borneo.

 

- T. p. saturatior (Salomonsen, 1933) breeds in the eastern parts of Nepal and northeastern India, in eastern Bangladesh and northern Myanmar; populations occurring in Malaysia migrate northward for breeding.[9]

 

- T. p. burmae (Salomonsen, 1933) inhabits the central region of Myanmar.

 

- T. p. indochinensis (Salomonsen, 1933) inhabits the eastern regions of Myanmar, Yunnan in the south of China, migrates through Thailand and Indochina to Malaysia, Sumatra and the neighboring islands.

  

Ecology and behaviour

 

Asian paradise flycatchers are noisy birds uttering sharp skreek calls. They have short legs and sit very upright whilst perched prominently, like a shrike. They are insectivorous and hunt in flight in the understorey. In the afternoons they dive from perches to bathe in small pools of water.

 

The breeding season lasts from May to July. Being socially monogamous both male and female take part in nest-building, incubation, brooding and feeding of the young. The incubation period lasts 14 to 16 days and the nestling period 9 to 12 days. Three or four eggs are laid in a neat cup nest made with twigs and spider webs on the end of a low branch. The nest is sometimes built in the vicinity of a breeding pair of drongos, which keep predators away. Chicks hatch in about 21 to 23 days. A case of interspecific feeding has been noted with paradise flycatcher chicks fed by Oriental white-eyes.

 

[Credit: en.wikipedia.org/]

Female. Light morph.

 

The females are polymorphic with at least two different morphs as far as I know.

The shell of the polymorphic snail Cepaea nemoralis, an example of logarithmic spiral. Edition (applied on the former snail image): shadows -> reduced; highlights -> enhanced; contrast -> slightly increased.

 

Focal length: 100 mm

Aperture: f/9.0

Exposure: 1/250 sec

ISO Speed: 100

Cannabis (/ˈkænəbɪs/) is a genus of flowering plant that includes three species (and seven taxa) or subspecies, sativa, indica, and ruderalis. The plant is indigenous to central Asia and the Indian subcontinent.

 

Cannabis has long been used for hemp fibre, for hemp oils, for medicinal purposes, and as a recreational drug. Industrial hemp products are made from cannabis plants selected to produce an abundance of fiber. To satisfy the UN Narcotics Convention, some cannabis strains have been bred to produce minimal levels of tetrahydrocannabinol (THC), the principal psychoactive constituent. Many plants have been selectively bred to produce a maximum of THC (cannabinoids), which is obtained by curing the flowers. Various compounds, including hashish and hash oil, are extracted from the plant.

 

Globally, in 2013, 60,400 kilograms of cannabis were produced legally. In 2013 between 128 and 232 million people are thought to have used cannabis as a recreational drug (2.7% to 4.9% of the global population between the ages of 15 and 65).

 

DESCIPTION

Cannabis is an annual, dioecious, flowering herb. The leaves are palmately compound or digitate, with serrate leaflets. The first pair of leaves usually have a single leaflet, the number gradually increasing up to a maximum of about thirteen leaflets per leaf (usually seven or nine), depending on variety and growing conditions. At the top of a flowering plant, this number again diminishes to a single leaflet per leaf. The lower leaf pairs usually occur in an opposite leaf arrangement and the upper leaf pairs in an alternate arrangement on the main stem of a mature plant.

 

The leaves have a peculiar and diagnostic venation pattern that enables persons poorly familiar with the plant to distinguish a cannabis leaf from unrelated species that have confusingly similar leaves (see illustration). As is common in serrated leaves, each serration has a central vein extending to its tip. However, the serration vein originates from lower down the central vein of the leaflet, typically opposite to the position of, not the first notch down, but the next notch. This means that on its way from the midrib of the leaflet to the point of the serration, the vein serving the tip of the serration passes close by the intervening notch. Sometimes the vein will actually pass tangent to the notch, but often it will pass by at a small distance, and when that happens a spur vein (occasionally a pair of such spur veins) branches off and joins the leaf margin at the deepest point of the notch. This venation pattern varies slightly among varieties, but in general it enables one to tell Cannabis leaves from superficially similar leaves without difficulty and without special equipment. Tiny samples of Cannabis plants also can be identified with precision by microscopic examination of leaf cells and similar features, but that requires special expertise and equipment.

 

The plant is believed to have originated in the mountainous regions northwest of the Himalayas.[citation needed] It is also known as hemp, although this term is often used to refer only to varieties of Cannabis cultivated for non-drug use.

 

REPRODUCTION

Cannabis normally has imperfect flowers, with staminate "male" and pistillate "female" flowers occurring on separate plants. It is not unusual, however, for individual plants to bear both male and female flowers. Although monoecious plants are often referred to as "hermaphrodites", true hermaphrodites (which are less common) bear staminate and pistillate structures on individual flowers, whereas monoecious plants bear male and female flowers at different locations on the same plant. Male flowers are normally borne on loose panicles, and female flowers are borne on racemes. "At a very early period the Chinese recognized the Cannabis plant as dioecious", and the (c. 3rd century BCE) Erya dictionary defined xi 枲 "male Cannabis" and fu 莩 (or ju 苴) "female Cannabis".

 

All known strains of Cannabis are wind-pollinated and the fruit is an achene. Most strains of Cannabis are short day plants, with the possible exception of C. sativa subsp. sativa var. spontanea (= C. ruderalis), which is commonly described as "auto-flowering" and may be day-neutral.

 

BIOCHEMISTRY AND DRUGS

Cannabis plants produce a group of chemicals called cannabinoids, which produce mental and physical effects when consumed.

 

Cannabinoids, terpenoids, and other compounds are secreted by glandular trichomes that occur most abundantly on the floral calyxes and bracts of female plants. As a drug it usually comes in the form of dried flower buds (marijuana), resin (hashish), or various extracts collectively known as hashish oil. In the early 20th century, it became illegal in most of the world to cultivate or possess Cannabis for sale or personal use.

 

CHROMOSOMES AND GENOME

Cannabis, like many organisms, is diploid, having a chromosome complement of 2n=20, although polyploid individuals have been artificially produced. The first genome sequence of Cannabis, which is estimated to be 820 Mb in size, was published in 2011 by a team of Canadian scientists.

 

TAXONOMY

The genus Cannabis was formerly placed in the Nettle (Urticaceae) or Mulberry (Moraceae) family, and later, along with the Humulus genus (hops), in a separate family, the Hemp family (Cannabaceae sensu stricto). Recent phylogenetic studies based on cpDNA restriction site analysis and gene sequencing strongly suggest that the Cannabaceae sensu stricto arose from within the former Celtidaceae family, and that the two families should be merged to form a single monophyletic family, the Cannabaceae sensu lato.

 

Various types of Cannabis have been described, and variously classified as species, subspecies, or varieties:

 

- plants cultivated for fiber and seed production, described as low-intoxicant, non-drug, or fiber types.

- plants cultivated for drug production, described as high-intoxicant or drug types.

- escaped, hybridised, or wild forms of either of the above types.

 

Cannabis plants produce a unique family of terpeno-phenolic compounds called cannabinoids, which produce the "high" one experiences from consuming marijuana. There are 483 identifiable chemical constituents known to exist in the cannabis plant, and at least 85 different cannabinoids have been isolated from the plant. The two cannabinoids usually produced in greatest abundance are cannabidiol (CBD) and/or Δ9-tetrahydrocannabinol (THC), but only THC is psychoactive. Since the early 1970s, Cannabis plants have been categorized by their chemical phenotype or "chemotype", based on the overall amount of THC produced, and on the ratio of THC to CBD. Although overall cannabinoid production is influenced by environmental factors, the THC/CBD ratio is genetically determined and remains fixed throughout the life of a plant. Non-drug plants produce relatively low levels of THC and high levels of CBD, while drug plants produce high levels of THC and low levels of CBD. When plants of these two chemotypes cross-pollinate, the plants in the first filial (F1) generation have an intermediate chemotype and produce similar amounts of CBD and THC. Female plants of this chemotype may produce enough THC to be utilized for drug production.

 

Whether the drug and non-drug, cultivated and wild types of Cannabis constitute a single, highly variable species, or the genus is polytypic with more than one species, has been a subject of debate for well over two centuries. This is a contentious issue because there is no universally accepted definition of a species. One widely applied criterion for species recognition is that species are "groups of actually or potentially interbreeding natural populations which are reproductively isolated from other such groups." Populations that are physiologically capable of interbreeding, but morphologically or genetically divergent and isolated by geography or ecology, are sometimes considered to be separate species. Physiological barriers to reproduction are not known to occur within Cannabis, and plants from widely divergent sources are interfertile. However, physical barriers to gene exchange (such as the Himalayan mountain range) might have enabled Cannabis gene pools to diverge before the onset of human intervention, resulting in speciation. It remains controversial whether sufficient morphological and genetic divergence occurs within the genus as a result of geographical or ecological isolation to justify recognition of more than one species.

 

HISTORY OF CANNABIS

Cannabis sativa appears naturally in many tropical and humid parts of the world. Its use as a mind-altering drug has been documented by archaeological finds in prehistoric societies in Euro-Asia and Africa.

 

The oldest written record of cannabis usage is the Greek historian Herodotus's reference to the central Eurasian Scythians taking cannabis steam baths. His (c. 440 BCE) Histories records, "The Scythians, as I said, take some of this hemp-seed [presumably, flowers], and, creeping under the felt coverings, throw it upon the red-hot stones; immediately it smokes, and gives out such a vapour as no Grecian vapour-bath can exceed; the Scyths, delighted, shout for joy." Classical Greeks and Romans were using cannabis, while in the Middle East, use spread throughout the Islamic empire to North Africa. In 1545 cannabis spread to the western hemisphere where Spaniards imported it to Chile for its use as fiber. In North America cannabis, in the form of hemp, was grown for use in rope, clothing and paper.

 

EARLY CLASSIFICATIONS

The Cannabis genus was first classified using the "modern" system of taxonomic nomenclature by Carl Linnaeus in 1753, who devised the system still in use for the naming of species. He considered the genus to be monotypic, having just a single species that he named Cannabis sativa L. (L. stands for Linnaeus, and indicates the authority who first named the species). Linnaeus was familiar with European hemp, which was widely cultivated at the time. In 1785, noted evolutionary biologist Jean-Baptiste de Lamarck published a description of a second species of Cannabis, which he named Cannabis indica Lam. Lamarck based his description of the newly named species on plant specimens collected in India. He described C. indica as having poorer fiber quality than C. sativa, but greater utility as an inebriant. Additional Cannabis species were proposed in the 19th century, including strains from China and Vietnam (Indo-China) assigned the names Cannabis chinensis Delile, and Cannabis gigantea Delile ex Vilmorin. However, many taxonomists found these putative species difficult to distinguish. In the early 20th century, the single-species concept was still widely accepted, except in the Soviet Union where Cannabis continued to be the subject of active taxonomic study. The name Cannabis indica was listed in various Pharmacopoeias, and was widely used to designate Cannabis suitable for the manufacture of medicinal preparations.

 

20TH CENTURY

In 1924, Russian botanist D.E. Janichevsky concluded that ruderal Cannabis in central Russia is either a variety of C. sativa or a separate species, and proposed C. sativa L. var. ruderalis Janisch. and Cannabis ruderalis Janisch. as alternative names. In 1929, renowned plant explorer Nikolai Vavilov assigned wild or feral populations of Cannabis in Afghanistan to C. indica Lam. var. kafiristanica Vav., and ruderal populations in Europe to C. sativa L. var. spontanea Vav. In 1940, Russian botanists Serebriakova and Sizov proposed a complex classification in which they also recognized C. sativa and C. indica as separate species. Within C. sativa they recognized two subspecies: C. sativa L. subsp. culta Serebr. (consisting of cultivated plants), and C. sativa L. subsp. spontanea (Vav.) Serebr. (consisting of wild or feral plants). Serebriakova and Sizov split the two C. sativa subspecies into 13 varieties, including four distinct groups within subspecies culta. However, they did not divide C. indica into subspecies or varieties. This excessive splitting of C. sativa proved too unwieldy, and never gained many adherents.

 

In the 1970s, the taxonomic classification of Cannabis took on added significance in North America. Laws prohibiting Cannabis in the United States and Canada specifically named products of C. sativa as prohibited materials. Enterprising attorneys for the defense in a few drug busts argued that the seized Cannabis material may not have been C. sativa, and was therefore not prohibited by law. Attorneys on both sides recruited botanists to provide expert testimony. Among those testifying for the prosecution was Dr. Ernest Small, while Dr. Richard E. Schultes and others testified for the defense. The botanists engaged in heated debate (outside of court), and both camps impugned the other's integrity. The defense attorneys were not often successful in winning their case, because the intent of the law was clear.

 

In 1976, Canadian botanist Ernest Small and American taxonomist Arthur Cronquist published a taxonomic revision that recognizes a single species of Cannabis with two subspecies: C. sativa L. subsp. sativa, and C. sativa L. subsp. indica (Lam.) Small & Cronq. The authors hypothesized that the two subspecies diverged primarily as a result of human selection; C. sativa subsp. sativa was presumably selected for traits that enhance fiber or seed production, whereas C. sativa subsp. indica was primarily selected for drug production. Within these two subspecies, Small and Cronquist described C. sativa L. subsp. sativa var. spontanea Vav. as a wild or escaped variety of low-intoxicant Cannabis, and C. sativa subsp. indica var. kafiristanica (Vav.) Small & Cronq. as a wild or escaped variety of the high-intoxicant type. This classification was based on several factors including interfertility, chromosome uniformity, chemotype, and numerical analysis of phenotypic characters.

 

Professors William Emboden, Loran Anderson, and Harvard botanist Richard E. Schultes and coworkers also conducted taxonomic studies of Cannabis in the 1970s, and concluded that stable morphological differences exist that support recognition of at least three species, C. sativa, C. indica, and C. ruderalis. For Schultes, this was a reversal of his previous interpretation that Cannabis is monotypic, with only a single species. According to Schultes' and Anderson's descriptions, C. sativa is tall and laxly branched with relatively narrow leaflets, C. indica is shorter, conical in shape, and has relatively wide leaflets, and C. ruderalis is short, branchless, and grows wild in central Asia. This taxonomic interpretation was embraced by Cannabis aficionados who commonly distinguish narrow-leafed "sativa" drug strains from wide-leafed "indica" drug strains.

 

CONTINUING RESEARCH

Molecular analytical techniques developed in the late 20th century are being applied to questions of taxonomic classification. This has resulted in many reclassifications based on evolutionary systematics. Several studies of Random Amplified Polymorphic DNA (RAPD) and other types of genetic markers have been conducted on drug and fiber strains of Cannabis, primarily for plant breeding and forensic purposes. Dutch Cannabis researcher E.P.M. de Meijer and coworkers described some of their RAPD studies as showing an "extremely high" degree of genetic polymorphism between and within populations, suggesting a high degree of potential variation for selection, even in heavily selected hemp cultivars. They also commented that these analyses confirm the continuity of the Cannabis gene pool throughout the studied accessions, and provide further confirmation that the genus comprises a single species, although theirs was not a systematic study per se.

 

Karl W. Hillig, a graduate student in the laboratory of long-time Cannabis researcher Paul G. Mahlberg at Indiana University, conducted a systematic investigation of genetic, morphological, and chemotaxonomic variation among 157 Cannabis accessions of known geographic origin, including fiber, drug, and feral populations. In 2004, Hillig and Mahlberg published a chemotaxomic analysis of cannabinoid variation in their Cannabis germplasm collection. They used gas chromatography to determine cannabinoid content and to infer allele frequencies of the gene that controls CBD and THC production within the studied populations, and concluded that the patterns of cannabinoid variation support recognition of C. sativa and C. indica as separate species, but not C. ruderalis. The authors assigned fiber/seed landraces and feral populations from Europe, central Asia, and Asia Minor to C. sativa. Narrow-leaflet and wide-leaflet drug accessions, southern and eastern Asian hemp accessions, and feral Himalayan populations were assigned to C. indica. In 2005, Hillig published a genetic analysis of the same set of accessions (this paper was the first in the series, but was delayed in publication), and proposed a three-species classification, recognizing C. sativa, C. indica, and (tentatively) C. ruderalis. In his doctoral dissertation published the same year, Hillig stated that principal components analysis of phenotypic (morphological) traits failed to differentiate the putative species, but that canonical variates analysis resulted in a high degree of discrimination of the putative species and infraspecific taxa. Another paper in the series on chemotaxonomic variation in the terpenoid content of the essential oil of Cannabis revealed that several wide-leaflet drug strains in the collection had relatively high levels of certain sesquiterpene alcohols, including guaiol and isomers of eudesmol, that set them apart from the other putative taxa. Hillig concluded that the patterns of genetic, morphological, and chemotaxonomic variation support recognition of C. sativa and C. indica as separate species. He also concluded there is little support to treat C. ruderalis as a separate species from C. sativa at this time, but more research on wild and weedy populations is needed because they were underrepresented in their collection.

 

In September 2005, New Scientist reported that researchers at the Canberra Institute of Technology had identified a new type of Cannabis based on analysis of mitochondrial and chloroplast DNA. The New Scientist story, which was picked up by many news agencies and web sites, indicated that the research was to be published in the journal Forensic Science International.

 

POPULAR USAGE

The scientific debate regarding taxonomy has had little effect on the terminology in widespread use among cultivators and users of drug-type Cannabis. Cannabis aficionados recognize three distinct types based on such factors as morphology, native range, aroma, and subjective psychoactive characteristics. Sativa is the most widespread variety, which is usually tall, laxly branched, and found in warm lowland regions. Indica designates shorter, bushier plants adapted to cooler climates and highland environments. Ruderalis is the informal name for the short plants that grow wild in Europe and central Asia.

 

Breeders, seed companies, and cultivators of drug type Cannabis often describe the ancestry or gross phenotypic characteristics of cultivars by categorizing them as "pure indica", "mostly indica", "indica/sativa", "mostly sativa", or "pure sativa".

 

USES

Cannabis is used for a wide variety of purposes.

 

RECREATIONAL USE

Cannabis is a popular recreational drug around the world, only behind alcohol, caffeine and tobacco. In the United States alone, it is believed that over 100 million Americans have tried cannabis, with 25 million Americans having used it within the past year.

 

The psychoactive effects of cannabis are known to have a biphasic nature. Primary psychoactive effects include a state of relaxation, and to a lesser degree, euphoria from its main psychoactive compound, tetrahydrocannabinol. Secondary psychoactive effects, such as a facility for philosophical thinking, introspection and metacognition have been reported amongst cases of anxiety and paranoia. Finally, the tertiary psychoactive effects of the drug cannabis, can include an increase in heart rate and hunger, believed to be caused by 11-OH-THC, a psychoactive metabolite of THC produced in the liver.

 

Normal cognition is restored after approximately three hours for larger doses via a smoking pipe, bong or vaporizer. However, if a large amount is taken orally the effects may last much longer. After 24 hours to a few days, minuscule psychoactive effects may be felt, depending on dosage, frequency and tolerance to the drug.

 

Various forms of the drug cannabis exist, including extracts such as hashish and hash oil which, because of appearance, are more susceptible to adulterants when left unregulated.

 

Cannabidiol (CBD), which has no psychotropic effects by itself (although sometimes showing a small stimulant effect, similar to caffeine), attenuates, or reduces the higher anxiety levels caused by THC alone.

 

According to Delphic analysis by British researchers in 2007, cannabis has a lower risk factor for dependence compared to both nicotine and alcohol. However, everyday use of Cannabis can in some cases be correlated with psychological withdrawal symptoms such as irritability and insomnia, and evidence could suggest that if a user experiences stress, the likeliness of getting a panic attack increases because of an increase of THC metabolites. However, cannabis withdrawal symptoms are typically mild and are never life-threatening.

 

MEDICAL USE

Medical cannabis (or medical marijuana) refers to the use of cannabis and its constituent cannabinoids, to treat disease or improve symptoms. Cannabis is used to reduce nausea and vomiting during chemotherapy, to improve appetite in people with HIV/AIDS, and to treat chronic pain and muscle spasms.

 

Short-term use increases both minor and major adverse effects. Common side effects include dizziness, feeling tired, vomiting, and hallucinations. Long-term effects of cannabis are not clear. Concerns including memory and cognition problems, risk of addiction, schizophrenia in young people, and the risk of children taking it by accident.

 

Cannabinoids are under preliminary research for their potential to affect stroke or children's epilepsy.

Industrial use (Hemp)

 

The term hemp is used to name the durable soft fiber from the Cannabis plant stem (stalk). Cannabis sativa cultivars are used for fibers due to their long stems; Sativa varieties may grow more than six metres tall. However, hemp can refer to any industrial or foodstuff product that is not intended for use as a drug. Many countries regulate limits for psychoactive compound (THC) concentrations in products labeled as hemp.

 

Cannabis for industrial uses is valuable in tens of thousands of commercial products, especially as fibre ranging from paper, cordage, construction material and textiles in general, to clothing. Hemp is stronger and longer-lasting than cotton. It also is a useful source of foodstuffs (hemp milk, hemp seed, hemp oil) and biofuels. Hemp has been used by many civilizations, from China to Europe (and later North America) during the last 12,000 years. In modern times novel applications and improvements have been explored with modest commercial success.

 

ANCIENT AND RELIGIOUS USE

The Cannabis plant has a history of medicinal use dating back thousands of years across many cultures. The Yanghai Tombs, a vast ancient cemetery (54 000 m2) situated in the Turfan district of the Xinjiang Uyghur Autonomous Region of the People's Republic of China, have revealed the 2700-year-old grave of a shaman. He is thought to have belonged to the Jushi culture recorded in the area centuries later in the Hanshu, Chap 96B. Near the head and foot of the shaman was a large leather basket and wooden bowl filled with 789g of cannabis, superbly preserved by climatic and burial conditions. An international team demonstrated that this material contained tetrahydrocannabinol, the psychoactive component of cannabis. The cannabis was presumably employed by this culture as a medicinal or psychoactive agent, or an aid to divination. This is the oldest documentation of cannabis as a pharmacologically active agent.

 

Settlements which date from c. 2200–1700 BCE in the Bactria and Margiana contained elaborate ritual structures with rooms containing everything needed for making drinks containing extracts from poppy (opium), hemp (cannabis), and ephedra (which contains ephedrine).

 

"While we have no evidence of the use of ephedra among the steppe tribes, we have already seen that they did share in the cultic use of hemp, a practice that ranged from Romania east to the Yenisei River from at least the 3rd millennium BC onwards where its use was later encountered in the apparatus for smoking hemp found at Pazyryk."

 

Cannabis is first referred to in Hindu Vedas between 2000 and 1400 BCE, in the Atharvaveda. By the 10th century CE, it has been suggested that it was referred to by some in India as "food of the gods". Cannabis use eventually became a ritual part of the Hindu festival of Holi.

 

In Buddhism, cannabis is generally regarded as an intoxicant and may be a hindrance to development of meditation and clear awareness. In ancient Germanic culture, Cannabis was associated with the Norse love goddess, Freya. An anointing oil mentioned in Exodus is, by some translators, said to contain Cannabis. Sufis have used Cannabis in a spiritual context since the 13th century CE.

 

In modern times the Rastafari movement has embraced Cannabis as a sacrament. Elders of the Ethiopian Zion Coptic Church, a religious movement founded in the United States in 1975 with no ties to either Ethiopia or the Coptic Church, consider Cannabis to be the Eucharist, claiming it as an oral tradition from Ethiopia dating back to the time of Christ. Like the Rastafari, some modern Gnostic Christian sects have asserted that Cannabis is the Tree of Life. Other organized religions founded in the 20th century that treat Cannabis as a sacrament are the THC Ministry, Cantheism,[101] the Cannabis Assembly and the Church of Cognizance. Rastafarians tend to be among the biggest consumers of modern Cannabis use.

 

Clay pipes at William Shakespeare's Stratford-upon-Avon garden may contain cannabis, indicating that Shakespeare may have been a cannabis smoker.

 

REPRODUCTION

BREEDING SYSTEMS

Cannabis is predominantly dioecious, although many monoecious varieties have been described. Subdioecy (the occurrence of monoecious individuals and dioecious individuals within the same population) is widespread. Many populations have been described as sexually labile. As a result of intensive selection in cultivation, Cannabis exhibits many sexual phenotypes that can be described in terms of the ratio of female to male flowers occurring in the individual, or typical in the cultivar. Dioecious varieties are preferred for drug production, where the female flowers are used. Dioecious varieties are also preferred for textile fiber production, whereas monoecious varieties are preferred for pulp and paper production. It has been suggested that the presence of monoecy can be used to differentiate licit crops of monoecious hemp from illicit drug crops. However, sativa strains often produce monoecious individuals, probably as a result of inbreeding.

 

SEX DETERMINATION

Cannabis has been described as having one of the most complicated mechanisms of sex determination among the dioecious plants. Many models have been proposed to explain sex determination in Cannabis.

 

Based on studies of sex reversal in hemp, it was first reported by K. Hirata in 1924 that an XY sex-determination system is present. At the time, the XY system was the only known system of sex determination. The X:A system was first described in Drosophila spp in 1925. Soon thereafter, Schaffner disputed Hirata's interpretation, and published results from his own studies of sex reversal in hemp, concluding that an X:A system was in use and that furthermore sex was strongly influenced by environmental conditions.

 

Since then, many different types of sex determination systems have been discovered, particularly in plants. Dioecy is relatively uncommon in the plant kingdom, and a very low percentage of dioecious plant species have been determined to use the XY system. In most cases where the XY system is found it is believed to have evolved recently and independently.

 

Since the 1920s, a number of sex determination models have been proposed for Cannabis. Ainsworth describes sex determination in the genus as using "an X/autosome dosage type".

 

The question of whether heteromorphic sex chromosomes are indeed present is most conveniently answered if such chromosomes were clearly visible in a karyotype. Cannabis was one of the first plant species to be karyotyped; however, this was in a period when karyotype preparation was primitive by modern standards (see History of Cytogenetics). Heteromorphic sex chromosomes were reported to occur in staminate individuals of dioecious "Kentucky" hemp, but were not found in pistillate individuals of the same variety. Dioecious "Kentucky" hemp was assumed to use an XY mechanism. Heterosomes were not observed in analyzed individuals of monoecious "Kentucky" hemp, nor in an unidentified German cultivar. These varieties were assumed to have sex chromosome composition XX. According to other researchers, no modern karyotype of Cannabis had been published as of 1996. Proponents of the XY system state that Y chromosome is slightly larger than the X, but difficult to differentiate cytologically.

 

More recently, Sakamoto and various co-authors have used RAPD to isolate several genetic marker sequences that they name Male-Associated DNA in Cannabis (MADC), and which they interpret as indirect evidence of a male chromosome. Several other research groups have reported identification of male-associated markers using RAPD and AFLP. Ainsworth commented on these findings, stating,

 

"It is not surprising that male-associated markers are relatively abundant. In dioecious plants where sex chromosomes have not been identified, markers for maleness indicate either the presence of sex chromosomes which have not been distinguished by cytological methods or that the marker is tightly linked to a gene involved in sex determination."

 

Environmental sex determination is known to occur in a variety of species. Many researchers have suggested that sex in Cannabis is determined or strongly influenced by environmental factors. Ainsworth reviews that treatment with auxin and ethylene have feminizing effects, and that treatment with cytokinins and gibberellins have masculinizing effects. It has been reported that sex can be reversed in Cannabis using chemical treatment. A PCR-based method for the detection of female-associated DNA polymorphisms by genotyping has been developed.

 

ETYMOLOGY

The word cannabis is from Greek κάνναβις (kánnabis) (see Latin cannabis), which was originally Scythian or Thracian. It is related to the Persian kanab, the English canvas and possibly even to the English hemp (Old English hænep). In modern Hebrew, קַנַּבּוֹס qannabōs (modern pronunciation: [kanaˈbos]) is used but there are those who have theorized that it was referred to in antiquity as קני בושם q'nei bosem, a component of the biblical anointing oil. Old Akkadian qunnabtu, Neo-Assyrian and Neo-Babylonian qunnabu were used to refer to the plant meaning "a way to produce smoke."

 

WIKIPEDIA

Alfred 23 Harth’s early formation can be read as a remarkable intertwining of play, discipline, and conceptual awakening that would later come to characterize his multidisciplinary oeuvre. The boyhood dream of becoming an architect already contained a telling dialectic: on the one hand, the imaginative freedom of building ephemeral huts in the garden, one after another; on the other hand, the precision of constructing variations within given parameters. These garden architectures were not merely child’s play but may be understood retrospectively as proto-installations, temporary structures that mediated between imagination and actuality, an early rehearsal of the experimental crossings between construction, performance, and image that marked Harth’s mature practice.

A decisive rupture, almost an initiation ritual into modern art, occurred in 1958 when his elder brother Dietrich took him to a Dada exhibition in Frankfurt am Main. The timing was crucial: postwar Germany was only just beginning to reopen itself to the radical avant-gardes suppressed under fascism. For the young Harth, Dada presented not only a set of provocative images but also the lived possibility that art could destabilize categories, break down hierarchies, and operate conceptually as much as materially. The work The Navel—a simple black dot on white paper, accompanied by a title that displaced perception into language—sharpened this awareness. What mattered was not the mark itself but the dynamic between sign and referent, artwork and its commentary. The epiphany here was not aesthetic pleasure in the traditional sense but recognition of art as a space of thought, irony, and intellectual tension. This was nothing less than the beginning of a lifelong trajectory in which Harth would consistently return to the interface of sound, image, and idea.

In the following years, Harth immersed himself with voracity in every available art medium. School courses gave him the discipline of drawing, painting, and craft; his own appetite for performance led him to stage small situations, often masked or disguised, anticipating the performative interventions of the happening movement. The acquisition of his first camera at twelve extended his field into visual experimentation, while his pencil drawings of jazz musicians revealed both his growing fascination with musical improvisation and his awareness of biography as a narrative lens for art. What is striking here is the simultaneity of practices—music, drawing, performance, photography—that refused to be subordinated to a single discipline. Even before formal professional training, Harth was cultivating a polymorphic artistic identity in the spirit of the avant-garde.

The turn at fifteen to oil painting coincided with a parallel transformation in music: the gift of a tenor saxophone by his parents, an instrument that would guide him into deep engagement with jazz and improvisation. This was not simply the adoption of a hobby but the entry point into an emerging identity as a musician-artist, one who would soon refuse to see music and art as separated categories. Music, drawing, film, and conceptual play converged into a holistic practice that aligned with the growing international awareness of intermedia arts in the 1960s.

Attending the Goethe Gymnasium in his final school years refined this eclecticism. As an art-focused program with an ambition to train future cultural producers, it provided him with a sweeping introduction to international avant-garde currents, from Informel painting and Fluxus to Concept Art and experimental film. What Harth absorbed was not only technique but also a certain intellectual ecology: Frankfurt at that time was a city where cultural exchange, experimental music, and critical thought interacted dynamically. Together with Hubertus Gassner, who would later become a prominent museum director, Harth initiated happenings and other art events. Harth and founded the centrum freier cunst. Such a venture signaled more than youthful ambition: it represented the determination to create autonomous platforms for hybrid work when established institutions remained largely indifferent. Here Harth’s music group Just Music performed alongside conceptual and photo-based works, embodying an ethos of cross-disciplinary experimentation that paralleled international movements but arose organically from the Frankfurt milieu.

By the time of his Abitur in 1968, Harth embodied a paradoxical combination: on the one hand, a youthful openness to every medium, on the other, a growing self-awareness of art as critical practice. His decision to study design at the Werkkunstschule Offenbach, later shifting to art pedagogy at Goethe University, should not be misunderstood as a retreat into conventional paths. Rather, it reflects his strategy of grounding avant-garde impulses in a broader discourse of form and teaching. His musical activities expanded concurrently, so that life at this junction became an intense negotiation of study, performance, and conceptual inquiry. Alfred Harth's focus on synästhetic creation was indeed a significant aspect of his artistic approach at that time. He was interested in exploring synaesthesia beyond traditional media like TV, film, or theater, aiming to realize multisensory or synästhetic works that integrated sound, visual elements, and space in novel ways. This approach reflected his broader interest in breaking conventional boundaries of artistic disciplines and engaging the audience in immersive, multi-layered experiences that could not be confined to a single medium or format.

Looking back, one sees that Harth’s early trajectory established key themes of his later career: the refusal of boundaries between disciplines; the privileging of concept and idea over medium-specificity; the creation of autonomous spaces for collaboration beyond institutional frameworks; and, above all, the conviction that art is not an object but a process—often ephemeral, contingent, and dialogic. The boy who once built huts in his parent’s garden was already rehearsing the logic of variation and improvisation that would structure his later works across music, performance, and visual art. To trace these beginnings is to see how Harth’s career was less a matter of progression from one discipline to another than an ongoing movement across media, always oriented toward the space where form touches thought.

  

Exhibit of toy camera images (Holga) at Soho Photo Gallery, NYC

Papilio memnon agenor , Great Mormon

 

Family: Papilionidae

Subfamily: Papilioninae

Genus Papilio

Species: memnon

Subspecies: agenor

Common Name: Great Mormon

Forms: esperi, butlerianus, agenor, ityla, tanahsahi, distantianus

Wingspan: 140-150 mm

 

Papilio memnon, the great Mormon, is a large butterfly native to southern Asia that belongs to the swallowtail family. It is widely distributed and has thirteen subspecies. The female is polymorphic and with mimetic forms.

 

Its range includes north-eastern India (including Sikkim, Assam and Nagaland), Nepal, Bangladesh, Myanmar, Nicobar Islands, Andaman Islands (stragglers only), western, southern and eastern China (including Hainan), Taiwan southern Japan, Ryukyu Islands, Thailand, Laos, Vietnam, Kampuchea, Malaysia and Indonesia (Sumatra, Mentawai Islands, Nias, Batu, Simeulue, Bangka, Java, Kalimantan and the Lesser Sunda Islands).

Maize (/meɪz/ MAYZ; Zea mays subsp. mays, from Spanish: maíz after Taino: mahiz), also known as corn (North American and Australian English), is a cereal grain first domesticated by indigenous peoples in southern Mexico about 10,000 years ago. The leafy stalk of the plant produces pollen inflorescences and separate ovuliferous inflorescences called ears that yield kernels or seeds, which are fruits.

 

Maize has become a staple food in many parts of the world, with the total production of maize surpassing that of wheat or rice. In addition to being consumed directly by humans (often in the form of masa), maize is also used for corn ethanol, animal feed and other maize products, such as corn starch and corn syrup. The six major types of maize are dent corn, flint corn, pod corn, popcorn, flour corn, and sweet corn. Sugar-rich varieties called sweet corn are usually grown for human consumption as kernels, while field corn varieties are used for animal feed, various corn-based human food uses (including grinding into cornmeal or masa, pressing into corn oil, and fermentation and distillation into alcoholic beverages like bourbon whiskey), and as chemical feedstocks. Maize is also used in making ethanol and other biofuels.

 

Maize is widely cultivated throughout the world, and a greater weight of maize is produced each year than any other grain. In 2014, total world production was 1.04 billion tonnes. Maize is the most widely grown grain crop throughout the Americas, with 361 million metric tons grown in the United States alone in 2014. Genetically modified maize made up 85% of the maize planted in the United States in 2009. Subsidies in the United States help to account for its high level of cultivation of maize and its position as the largest producer in the world.

 

HISTORY

PRE-COLUMBIAN DEVELOPMENT

Maize is a cultigen; human intervention is required for it to propagate. Whether or not the kernels fall off the cob on their own is a key piece of evidence used in archaeology to distinguish domesticated maize from its naturally-propagating teosinte ancestor. Genetic evidence can also be used to determine when various lineages split.

 

Most historians believe maize was domesticated in the Tehuacán Valley of Mexico. Recent research in the early 21st century has modified this view somewhat; scholars now indicate the adjacent Balsas River Valley of south-central Mexico as the center of domestication.

 

An influential 2002 study by Matsuoka et al. has demonstrated that, rather than the multiple independent domestications model, all maize arose from a single domestication in southern Mexico about 9,000 years ago. The study also demonstrated that the oldest surviving maize types are those of the Mexican highlands. Later, maize spread from this region over the Americas along two major paths. This is consistent with a model based on the archaeological record suggesting that maize diversified in the highlands of Mexico before spreading to the lowlands.

 

Archaeologist Dolores Piperno has said:

 

A large corpus of data indicates that [maize] was dispersed into lower Central America by 7600 BP [5600 BC] and had moved into the inter-Andean valleys of Colombia between 7000 and 6000 BP [5000–4000 BC].

— Dolores Piperno, The Origins of Plant Cultivation and Domestication in the New World Tropics: Patterns, Process, and New Developments

 

Since then, even earlier dates have been published.

 

According to a genetic study by Embrapa, corn cultivation was introduced in South America from Mexico, in two great waves: the first, more than 6000 years ago, spread through the Andes. Evidence of cultivation in Peru has been found dating to about 6700 years ago. The second wave, about 2000 years ago, through the lowlands of South America.

 

The earliest maize plants grew only small, 25-millimetre-long (1 in) corn cobs, and only one per plant. In Jackson Spielvogel's view, many centuries of artificial selection (rather than the current view that maize was exploited by interplanting with teosinte) by the indigenous people of the Americas resulted in the development of maize plants capable of growing several cobs per plant, which were usually several centimetres/inches long each. The Olmec and Maya cultivated maize in numerous varieties throughout Mesoamerica; they cooked, ground and processed it through nixtamalization. It was believed that beginning about 2500 BC, the crop spread through much of the Americas. Research of the 21st century has established even earlier dates. The region developed a trade network based on surplus and varieties of maize crops.

 

Mapuches of south-central Chile cultivated maize along with quinoa and potatoes in pre-Hispanic times; however, potato was the staple food of most Mapuches, "specially in the southern and coastal [Mapuche] territories where maize did not reach maturity". Before the expansion of the Inca Empire maize was traded and transported as far south as 40°19' S in Melinquina, Lácar Department. In that location maize remains were found inside pottery dated to 730 ± 80 BP and 920 ± 60 BP. Probably this maize was brought across the Andes from Chile. The presence of maize in Guaitecas Archipelago (43°55' S), the southernmost outpost of pre-Hispanic agriculture, is reported by early Spanish explorers. However the Spanish may have misidentified the plant.

 

COLUMBIAN EXCHANGE

After the arrival of Europeans in 1492, Spanish settlers consumed maize, and explorers and traders carried it back to Europe and introduced it to other countries. Spanish settlers far preferred wheat bread to maize, cassava, or potatoes. Maize flour could not be substituted for wheat for communion bread, since in Christian belief only wheat could undergo transubstantiation and be transformed into the body of Christ. Some Spaniards worried that by eating indigenous foods, which they did not consider nutritious, they would weaken and risk turning into Indians. "In the view of Europeans, it was the food they ate, even more than the environment in which they lived, that gave Amerindians and Spaniards both their distinctive physical characteristics and their characteristic personalities." Despite these worries, Spaniards did consume maize. Archeological evidence from Florida sites indicate they cultivated it as well.

 

Maize spread to the rest of the world because of its ability to grow in diverse climates. It was cultivated in Spain just a few decades after Columbus's voyages and then spread to Italy, West Africa and elsewhere. Widespread cultivation most likely began in southern Spain in 1525, after which it quickly spread to the rest of the Spanish Empire including its territories in Italy (and, from there, to other Italian states). Maize had many advantages over wheat and barley; it yielded two and a half times the food energy per unit cultivated area, could be harvested in successive years from the same plot of land, and grew in wildly varying altitudes and climates, from relatively dry regions with only 250 mm (10 in) of annual rainfall to damp regions with over 5,000 mm (200 in). By the 17th century it was a common peasant food in Southwestern Europe, including Portugal, Spain, southern France, and Italy. By the 18th century, it was the chief food of the southern French and Italian peasantry, especially in the form of polenta in Italy.

Names

 

The word maize derives from the Spanish form of the indigenous Taíno word for the plant, mahiz. It is known by other names around the world.

 

The word "corn" outside the US, Canada, Australia, and New Zealand refers to any cereal crop, its meaning understood to vary geographically to refer to the local staple. In the United States, Canada, Australia, and New Zealand, corn primarily means maize; this usage started as a shortening of "Indian corn". "Indian corn" primarily means maize (the staple grain of indigenous Americans), but can refer more specifically to multicolored "flint corn" used for decoration.

 

In places outside the US, Canada, Australia, and New Zealand, corn often refers to maize in culinary contexts. The narrower meaning is usually indicated by some additional word, as in sweet corn, sweetcorn, corn on the cob, baby corn, the puffed confection known as popcorn and the breakfast cereal known as corn flakes.

 

In Southern Africa, maize is commonly called mielie (Afrikaans) or mealie (English), words derived from the Portuguese word for maize, milho.

 

Maize is preferred in formal, scientific, and international usage because it refers specifically to this one grain, unlike corn, which has a complex variety of meanings that vary by context and geographic region. Maize is used by agricultural bodies and research institutes such as the FAO and CSIRO. National agricultural and industry associations often include the word maize in their name even in English-speaking countries where the local, informal word is something other than maize; for example, the Maize Association of Australia, the Indian Maize Development Association, the Kenya Maize Consortium and Maize Breeders Network, the National Maize Association of Nigeria, the Zimbabwe Seed Maize Association.

 

STRUCTURE AND PHYSIOLOGY

The maize plant is often 3 m (10 ft) in height, though some natural strains can grow 13 m (43 ft). The stem is commonly composed of 20 internodes of 18 cm (7 in) length. The leaves arise from the nodes, alternately on opposite sides on the stalk. A leaf, which grows from each node, is generally 9 cm (3+1⁄2 in) in width and 120 cm (3 ft 11 in) in length.

 

Ears develop above a few of the leaves in the midsection of the plant, between the stem and leaf sheath, elongating by around 3 mm (1⁄8 in) per day, to a length of 18 cm (7 in) with 60 cm (24 in) being the maximum alleged in the subspecies. They are female inflorescences, tightly enveloped by several layers of ear leaves commonly called husks. Certain varieties of maize have been bred to produce many additional developed ears. These are the source of the "baby corn" used as a vegetable in Asian cuisine.

 

The apex of the stem ends in the tassel, an inflorescence of male flowers. When the tassel is mature and conditions are suitably warm and dry, anthers on the tassel dehisce and release pollen. Maize pollen is anemophilous (dispersed by wind), and because of its large settling velocity, most pollen falls within a few meters of the tassel.

 

Elongated stigmas, called silks, emerge from the whorl of husk leaves at the end of the ear. They are often pale yellow and 18 cm (7 in) in length, like tufts of hair in appearance. At the end of each is a carpel, which may develop into a "kernel" if fertilized by a pollen grain. The pericarp of the fruit is fused with the seed coat referred to as "caryopsis", typical of the grasses, and the entire kernel is often referred to as the "seed". The cob is close to a multiple fruit in structure, except that the individual fruits (the kernels) never fuse into a single mass. The grains are about the size of peas, and adhere in regular rows around a white, pithy substance, which forms the ear. The maximum size of kernels is reputedly 2.5 cm (1 in). An ear commonly holds 600 kernels. They are of various colors: blackish, bluish-gray, purple, green, red, white and yellow. When ground into flour, maize yields more flour with much less bran than wheat does. It lacks the protein gluten of wheat and, therefore, makes baked goods with poor rising capability. A genetic variant that accumulates more sugar and less starch in the ear is consumed as a vegetable and is called sweet corn. Young ears can be consumed raw, with the cob and silk, but as the plant matures (usually during the summer months), the cob becomes tougher and the silk dries to inedibility. By the end of the growing season, the kernels dry out and become difficult to chew without cooking them tender first in boiling water.

 

Planting density affects multiple aspects of maize. Modern farming techniques in developed countries usually rely on dense planting, which produces one ear per stalk. Stands of silage maize are yet denser,[citation needed] and achieve a lower percentage of ears and more plant matter.

 

Maize is a facultative short-day plant and flowers in a certain number of growing degree days > 10 °C (50 °F) in the environment to which it is adapted. The magnitude of the influence that long nights have on the number of days that must pass before maize flowers is genetically prescribed and regulated by the phytochrome system.

Photoperiodicity can be eccentric in tropical cultivars such that the long days characteristic of higher latitudes allow the plants to grow so tall that they do not have enough time to produce seed before being killed by frost. These attributes, however, may prove useful in using tropical maize for biofuels.

 

Immature maize shoots accumulate a powerful antibiotic substance, 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA). DIMBOA is a member of a group of hydroxamic acids (also known as benzoxazinoids) that serve as a natural defense against a wide range of pests, including insects, pathogenic fungi and bacteria. DIMBOA is also found in related grasses, particularly wheat. A maize mutant (bx) lacking DIMBOA is highly susceptible to attack by aphids and fungi. DIMBOA is also responsible for the relative resistance of immature maize to the European corn borer (family Crambidae). As maize matures, DIMBOA levels and resistance to the corn borer decline.

 

Because of its shallow roots, maize is susceptible to droughts, intolerant of nutrient-deficient soils, and prone to be uprooted by severe winds.

 

While yellow maizes derive their color from lutein and zeaxanthin, in red-colored maizes, the kernel coloration is due to anthocyanins and phlobaphenes. These latter substances are synthesized in the flavonoids synthetic pathway from polymerization of flavan-4-ols by the expression of maize pericarp color1 (p1) gene which encodes an R2R3 myb-like transcriptional activator of the A1 gene encoding for the dihydroflavonol 4-reductase (reducing dihydroflavonols into flavan-4-ols) while another gene (Suppressor of Pericarp Pigmentation 1 or SPP1) acts as a suppressor. The p1 gene encodes an Myb-homologous transcriptional activator of genes required for biosynthesis of red phlobaphene pigments, while the P1-wr allele specifies colorless kernel pericarp and red cobs, and unstable factor for orange1 (Ufo1) modifies P1-wr expression to confer pigmentation in kernel pericarp, as well as vegetative tissues, which normally do not accumulate significant amounts of phlobaphene pigments. The maize P gene encodes a Myb homolog that recognizes the sequence CCT/AACC, in sharp contrast with the C/TAACGG bound by vertebrate Myb proteins.

 

The ear leaf is the leaf most closely associated with a particular developing ear. This leaf and above contribute 70% to 75% to 90% of grain fill. Therefore fungicide application is most important in that region in most disease environments.

 

ABNORMAL FLOWERS

Maize flowers may sometimes exhibit mutations that lead to the formation of female flowers in the tassel. These mutations, ts4 and Ts6, prohibit the development of the stamen while simultaneously promoting pistil development. This may cause inflorescences containing both male and female flowers, or hermaphrodite flowers.

 

GENETICS

Maize is an annual grass in the family Gramineae, which includes such plants as wheat, rye, barley, rice, sorghum, and sugarcane. There are two major species of the genus Zea (out of six total): Zea mays (maize) and Zea diploperennis, which is a perennial type of teosinte. The annual teosinte variety called Zea mays mexicana is the closest botanical relative to maize. It still grows in the wild as an annual in Mexico and Guatemala.

 

Many forms of maize are used for food, sometimes classified as various subspecies related to the amount of starch each has:

 

Flour corn: Zea mays var. amylacea

Popcorn: Zea mays var. everta

Dent corn : Zea mays var. indentata

Flint corn: Zea mays var. indurata

Sweet corn: Zea mays var. saccharata and Zea mays var. rugosa

Waxy corn: Zea mays var. ceratina

Amylomaize: Zea mays

Pod corn: Zea mays var. tunicata Larrañaga ex A. St. Hil.

Striped maize: Zea mays var. japonica

 

This system has been replaced (though not entirely displaced) over the last 60 years by multivariable classifications based on ever more data. Agronomic data were supplemented by botanical traits for a robust initial classification, then genetic, cytological, protein and DNA evidence was added. Now, the categories are forms (little used), races, racial complexes, and recently branches.

 

Maize is a diploid with 20 chromosomes (n=10). The combined length of the chromosomes is 1500 cM. Some of the maize chromosomes have what are known as "chromosomal knobs": highly repetitive heterochromatic domains that stain darkly. Individual knobs are polymorphic among strains of both maize and teosinte.

 

Barbara McClintock used these knob markers to validate her transposon theory of "jumping genes", for which she won the 1983 Nobel Prize in Physiology or Medicine. Maize is still an important model organism for genetics and developmental biology today.

 

The centromeres have two types of structural components, both of which are found only in the centromeres: Large arrays of CentC, a short satellite DNA; and a few of a family of retrotransposons. The B chromosome, unlike the others, contains an additional repeat which extends into neighboring areas of the chromosome. Centromeres can accidentally shrink during division and still function, although it is thought this will fail if it shrinks below a few hundred kilobase. Kinetochores contain RNA originating from centromeres. Centromere regions can become inactive, and can continue in that state if the chromosome still has another active one.

 

The Maize Genetics Cooperation Stock Center, funded by the USDA Agricultural Research Service and located in the Department of Crop Sciences at the University of Illinois at Urbana-Champaign, is a stock center of maize mutants. The total collection has nearly 80,000 samples. The bulk of the collection consists of several hundred named genes, plus additional gene combinations and other heritable variants. There are about 1000 chromosomal aberrations (e.g., translocations and inversions) and stocks with abnormal chromosome numbers (e.g., tetraploids). Genetic data describing the maize mutant stocks as well as myriad other data about maize genetics can be accessed at MaizeGDB, the Maize Genetics and Genomics Database.

 

In 2005, the US National Science Foundation (NSF), Department of Agriculture (USDA) and the Department of Energy (DOE) formed a consortium to sequence the B73 maize genome. The resulting DNA sequence data was deposited immediately into GenBank, a public repository for genome-sequence data. Sequences and genome annotations have also been made available throughout the project's lifetime at the project's official site.

 

Primary sequencing of the maize genome was completed in 2008. On November 20, 2009, the consortium published results of its sequencing effort in Science. The genome, 85% of which is composed of transposons, was found to contain 32,540 genes (By comparison, the human genome contains about 2.9 billion bases and 26,000 genes). Much of the maize genome has been duplicated and reshuffled by helitrons—group of rolling circle transposons.

 

In Z. mays and various other angiosperms the MADS-box motif is involved in floral development. Early study in several angiosperm models including Z. mays was the beginning of research into the molecular evolution of floral structure in general, as well as their role in nonflowering plants.

 

EVOLUTION

As with many plants and animals, Z. mays has a positive correlation between effective population size and the magnitude of selection pressure. Z. m. having an EPS of ~650,000, it clusters with others of about the same EPS, and has 79% of its amino acid sites under selection.

 

Recombination is a significant source of diversity in Z. mays. (Note that this finding supersedes previous studies which showed no such correlation.)

 

This recombination/diversity effect is seen throughout plants but is also found to not occur – or not as strongly – in regions of high gene density. This is likely the reason that domesticated Z. mays has not seen as much of an increase in diversity within areas of higher density as in regions of lower density, although there is more evidence in other plants.

 

Some lines of maize have undergone ancient polyploidy events, starting 11m years ago. Over that time ~72% of polyploid duplicated genes have been retained, which is higher than other plants with older polyploidy events. Thus maize may be due to lose more duplicate genes as time goes along, similar to the course followed by the genomes of other plants. If so - if gene loss has merely not occurred yet - that could explain the lack of observed positive selection and lower negative selection which are observed in otherwise similar plants, i.e. also naturally outcrossing and with similar effective population sizes.

 

Ploidy does not appear to influence EPS or magnitude of selection effect in maize.

 

BREEDING

Maize reproduces sexually each year. This randomly selects half the genes from a given plant to propagate to the next generation, meaning that desirable traits found in the crop (like high yield or good nutrition) can be lost in subsequent generations unless certain techniques are used.

 

Maize breeding in prehistory resulted in large plants producing large ears. Modern breeding began with individuals who selected highly productive varieties in their fields and then sold seed to other farmers. James L. Reid was one of the earliest and most successful developing Reid's Yellow Dent in the 1860s. These early efforts were based on mass selection. Later breeding efforts included ear to row selection (C. G. Hopkins c. 1896), hybrids made from selected inbred lines (G. H. Shull, 1909), and the highly successful double cross hybrids using four inbred lines (D. F. Jones c. 1918, 1922). University supported breeding programs were especially important in developing and introducing modern hybrids. By the 1930s, companies such as Pioneer devoted to production of hybrid maize had begun to influence long-term development. Internationally important seed banks such as the International Maize and Wheat Improvement Center (CIMMYT) and the US bank at the Maize Genetics Cooperation Stock Center University of Illinois at Urbana-Champaign maintain germplasm important for future crop development.

 

Since the 1940s the best strains of maize have been first-generation hybrids made from inbred strains that have been optimized for specific traits, such as yield, nutrition, drought, pest and disease tolerance. Both conventional cross-breeding and genetic modification have succeeded in increasing output and reducing the need for cropland, pesticides, water and fertilizer. There is conflicting evidence to support the hypothesis that maize yield potential has increased over the past few decades. This suggests that changes in yield potential are associated with leaf angle, lodging resistance, tolerance of high plant density, disease/pest tolerance, and other agronomic traits rather than increase of yield potential per individual plant.

 

Tropical landraces remain an important and underutilized source of resistance alleles for for disease and for herbivores. Notable discoveries of rare alleles for this purpose were made by Dao et al 2014 and Sood et al 2014.

 

GLOBAL PROGRAM

CIMMYT operates a conventional breeding program to provide optimized strains. The program began in the 1980s. Hybrid seeds are distributed in Africa by the Drought Tolerant Maize for Africa project.

 

GENETIC MODIFICATION

Genetically modified (GM) maize was one of the 26 GM crops grown commercially in 2016. The vast majority of this is Bt maize. Grown since 1997 in the United States and Canada, 92% of the US maize crop was genetically modified in 2016 and 33% of the worldwide maize crop was GM in 2016. As of 2011, Herbicide-tolerant maize varieties were grown in Argentina, Australia, Brazil, Canada, China, Colombia, El Salvador, the European Union, Honduras, Japan, Korea, Malaysia, Mexico, New Zealand, Philippines, the Russian Federation, Singapore, South Africa, Taiwan, Thailand, and the United States. Insect-resistant maize was grown in Argentina, Australia, Brazil, Canada, Chile, China, Colombia, Egypt, the European Union, Honduras, Japan, Korea, Malaysia, Mexico, New Zealand, Philippines, South Africa, Switzerland, Taiwan, the United States, and Uruguay.

 

In September 2000, up to $50 million worth of food products were recalled due to the presence of Starlink genetically modified corn, which had been approved only for animal consumption and had not been approved for human consumption, and was subsequently withdrawn from the market.

 

ORIGIN

Maize is the domesticated variant of teosinte. The two plants have dissimilar appearance, maize having a single tall stalk with multiple leaves and teosinte being a short, bushy plant. The difference between the two is largely controlled by differences in just two genes, called grassy tillers-1 (gt1, A0A317YEZ1) and teosinte branched-1 (tb1, Q93WI2).

 

Several theories had been proposed about the specific origin of maize in Mesoamerica:

 

It is a direct domestication of a Mexican annual teosinte, Zea mays ssp. parviglumis, native to the Balsas River valley in south-eastern Mexico, with up to 12% of its genetic material obtained from Zea mays ssp. mexicana through introgression.

It has been derived from hybridization between a small domesticated maize (a slightly changed form of a wild maize) and a teosinte of section Luxuriantes, either Z. luxurians or Z. diploperennis.

It has undergone two or more domestications either of a wild maize or of a teosinte. (The term "teosinte" describes all species and subspecies in the genus Zea, excluding Zea mays ssp. mays.)

It has evolved from a hybridization of Z. diploperennis by Tripsacum dactyloides.

 

In the late 1930s, Paul Mangelsdorf suggested that domesticated maize was the result of a hybridization event between an unknown wild maize and a species of Tripsacum, a related genus. This theory about the origin of maize has been refuted by modern genetic testing, which refutes Mangelsdorf's model and the fourth listed above. 

 

The teosinte origin theory was proposed by the Russian botanist Nikolai Ivanovich Vavilov in 1931 and the later American Nobel Prize-winner George Beadle in 1932.: 10  It is supported experimentally and by recent studies of the plants' genomes. Teosinte and maize can cross-breed and produce fertile offspring. A number of questions remain concerning the species, among them:

 

how the immense diversity of the species of sect. Zea originated,

how the tiny archaeological specimens of 3500–2700 BC could have been selected from a teosinte, and

how domestication could have proceeded without leaving remains of teosinte or maize with teosintoid traits earlier than the earliest known until recently, dating from ca. 1100 BC.

 

The domestication of maize is of particular interest to researchers—archaeologists, geneticists, ethnobotanists, geographers, etc. The process is thought by some to have started 7,500 to 12,000 years ago. Research from the 1950s to 1970s originally focused on the hypothesis that maize domestication occurred in the highlands between the states of Oaxaca and Jalisco, because the oldest archaeological remains of maize known at the time were found there.

Connection with 'parviglumis' subspecies

Genetic studies, published in 2004 by John Doebley, identified Zea mays ssp. parviglumis, native to the Balsas River valley in Mexico's southwestern highlands, and also known as Balsas teosinte, as being the crop wild relative that is genetically most similar to modern maize. This was confirmed by further studies, which refined this hypothesis somewhat. Archaeobotanical studies, published in 2009, point to the middle part of the Balsas River valley as the likely location of early domestication; this river is not very long, so these locations are not very distant. Stone milling tools with maize residue have been found in an 8,700 year old layer of deposits in a cave not far from Iguala, Guerrero.

 

Doebley was part of the team that first published, in 2002, that maize had been domesticated only once, about 9,000 years ago, and then spread throughout the Americas.

 

A primitive corn was being grown in southern Mexico, Central America, and northern South America 7,000 years ago. Archaeological remains of early maize ears, found at Guila Naquitz Cave in the Oaxaca Valley, date back roughly 6,250 years; the oldest ears from caves near Tehuacan, Puebla, 5,450 B.P.

 

Maize pollen dated to 7,300 B.P. from San Andres, Tabasco, on the Caribbean coast has also been recovered.

 

As maize was introduced to new cultures, new uses were developed and new varieties selected to better serve in those preparations. Maize was the staple food, or a major staple – along with squash, Andean region potato, quinoa, beans, and amaranth – of most pre-Columbian North American, Mesoamerican, South American, and Caribbean cultures. The Mesoamerican civilization, in particular, was deeply interrelated with maize. Its traditions and rituals involved all aspects of maize cultivation – from the planting to the food preparation. Maize formed the Mesoamerican people's identity.

 

It is unknown what precipitated its domestication, because the edible portion of the wild variety is too small, and hard to obtain, to be eaten directly, as each kernel is enclosed in a very hard bivalve shell.

 

In 1939, George Beadle demonstrated that the kernels of teosinte are readily "popped" for human consumption, like modern popcorn. Some have argued it would have taken too many generations of selective breeding to produce large, compressed ears for efficient cultivation. However, studies of the hybrids readily made by intercrossing teosinte and modern maize suggest this objection is not well founded.

 

SPREADING TO THE NORTH

Around 4,500 ago, maize began to spread to the north; it was first cultivated in what is now the United States at several sites in New Mexico and Arizona, about 4,100 ago.

 

During the first millennium AD, maize cultivation spread more widely in the areas north. In particular, the large-scale adoption of maize agriculture and consumption in eastern North America took place about A.D. 900. Native Americans cleared large forest and grassland areas for the new crop.

 

In 2005, research by the USDA Forest Service suggested that the rise in maize cultivation 500 to 1,000 years ago in what is now the southeastern United States corresponded with a decline of freshwater mussels, which are very sensitive to environmental changes.

 

CULTIVATION

PLANTING

Because it is cold-intolerant, in the temperate zones maize must be planted in the spring. Its root system is generally shallow, so the plant is dependent on soil moisture. As a plant that uses C4 carbon fixation, maize is a considerably more water-efficient crop than plants that use C3 carbon fixation such as alfalfa and soybeans. Maize is most sensitive to drought at the time of silk emergence, when the flowers are ready for pollination. In the United States, a good harvest was traditionally predicted if the maize was "knee-high by the Fourth of July", although modern hybrids generally exceed this growth rate. Maize used for silage is harvested while the plant is green and the fruit immature. Sweet corn is harvested in the "milk stage", after pollination but before starch has formed, between late summer and early to mid-autumn. Field maize is left in the field until very late in the autumn to thoroughly dry the grain, and may, in fact, sometimes not be harvested until winter or even early spring. The importance of sufficient soil moisture is shown in many parts of Africa, where periodic drought regularly causes maize crop failure and consequent famine. Although it is grown mainly in wet, hot climates, it has been said to thrive in cold, hot, dry or wet conditions, meaning that it is an extremely versatile crop.

 

Maize was planted by the Native Americans in hills, in a complex system known to some as the Three Sisters. Maize provided support for beans, and the beans provided nitrogen derived from nitrogen-fixing rhizobia bacteria which live on the roots of beans and other legumes; and squashes provided ground cover to stop weeds and inhibit evaporation by providing shade over the soil. This method was replaced by single species hill planting where each hill 60–120 cm (2 ft 0 in–3 ft 11 in) apart was planted with three or four seeds, a method still used by home gardeners. A later technique was "checked maize", where hills were placed

 

1 m (40 in) apart in each direction, allowing cultivators to run through the field in two directions. In more arid lands, this was altered and seeds were planted in the bottom of 10–12 cm (4–4+1⁄2 in) deep furrows to collect water. Modern technique plants maize in rows which allows for cultivation while the plant is young, although the hill technique is still used in the maize fields of some Native American reservations. When maize is planted in rows, it also allows for planting of other crops between these rows to make more efficient use of land space.

 

In most regions today, maize grown in residential gardens is still often planted manually with a hoe, whereas maize grown commercially is no longer planted manually but rather is planted with a planter. In North America, fields are often planted in a two-crop rotation with a nitrogen-fixing crop, often alfalfa in cooler climates and soybeans in regions with longer summers. Sometimes a third crop, winter wheat, is added to the rotation.

 

Many of the maize varieties grown in the United States and Canada are hybrids. Often the varieties have been genetically modified to tolerate glyphosate or to provide protection against natural pests. Glyphosate is an herbicide which kills all plants except those with genetic tolerance. This genetic tolerance is very rarely found in nature.

 

In the midwestern United States, low-till or no-till farming techniques are usually used. In low-till, fields are covered once, maybe twice, with a tillage implement either ahead of crop planting or after the previous harvest. The fields are planted and fertilized. Weeds are controlled through the use of herbicides, and no cultivation tillage is done during the growing season. This technique reduces moisture evaporation from the soil, and thus provides more moisture for the crop. The technologies mentioned in the previous paragraph enable low-till and no-till farming. Weeds compete with the crop for moisture and nutrients, making them undesirable.

 

HARVESTING

Before the 20th century, all maize harvesting was by manual labour, by grazing, or by some combination of those. Whether the ears were hand-picked and the stover was grazed, or the whole plant was cut, gathered, and shocked, people and livestock did all the work. Between the 1890s and the 1970s, the technology of maize harvesting expanded greatly. Today, all such technologies, from entirely manual harvesting to entirely mechanized, are still in use to some degree, as appropriate to each farm's needs, although the thoroughly mechanized versions predominate, as they offer the lowest unit costs when scaled to large farm operations. For small farms, their unit cost can be too high, as their higher fixed cost cannot be amortized over as many units.[citation needed]

 

Before World War II, most maize in North America was harvested by hand. This involved a large number of workers and associated social events (husking or shucking bees). From the 1890s onward, some machinery became available to partially mechanize the processes, such as one- and two-row mechanical pickers (picking the ear, leaving the stover) and corn binders, which are reaper-binders designed specifically for maize (for example, Video on YouTube). The latter produce sheaves that can be shocked. By hand or mechanical picker, the entire ear is harvested, which then requires a separate operation of a maize sheller to remove the kernels from the ear. Whole ears of maize were often stored in corn cribs, and these whole ears are a sufficient form for some livestock feeding use. Today corn cribs with whole ears, and corn binders, are less common because most modern farms harvest the grain from the field with a combine and store it in bins. The combine with a corn head (with points and snap rolls instead of a reel) does not cut the stalk; it simply pulls the stalk down. The stalk continues downward and is crumpled into a mangled pile on the ground, where it usually is left to become organic matter for the soil. The ear of maize is too large to pass between slots in a plate as the snap rolls pull the stalk away, leaving only the ear and husk to enter the machinery. The combine separates the husk and the cob, keeping only the kernels.

When maize is a silage crop, the entire plant is usually chopped at once with a forage harvester (chopper) and ensiled in silos or polymer wrappers. Ensiling of sheaves cut by a corn binder was formerly common in some regions but has become uncommon. For storing grain in bins, the moisture of the grain must be sufficiently low to avoid spoiling. If the moisture content of the harvested grain is too high, grain dryers are used to reduce the moisture content by blowing heated air through the grain. This can require large amounts of energy in the form of combustible gases (propane or natural gas) and electricity to power the blowers.

 

PRODUCTION

Maize is widely cultivated throughout the world, and a greater weight of maize is produced each year than any other grain. In 2018, total world production was 1.15 billion tonnes, led by the United States with 34.2% of the total (table). China produced 22.4% of the global total.

 

UNITED STATES

In 2016, maize production was forecast to be over 380 million metric tons (15 billion bushels), an increase of 11% over 2014 American production. Based on conditions as of August 2016, the expected yield would be the highest ever for the United States. The area of harvested maize was forecast to be 35 million hectares (87 million acres), an increase of 7% over 2015. Maize is especially popular in Midwestern states such as Indiana, Iowa, and Illinois; in the latter, it was named the state's official grain in 2017.

 

STORAGE

Drying is vital to prevent or at least reduce mycotoxin contamination. Aspergillus and Fusarium spp. are the most common mycotoxin sources, but there are others. Altogether maize contaminants are so common, and this crop is so economically important, that maize mycotoxins are among the most important in agriculture in general.

 

USES

HUMAN FOOD

Maize and cornmeal (ground dried maize) constitute a staple food in many regions of the world. Maize is used to produce cornstarch, a common ingredient in home cooking and many industrialized food products. Maize starch can be hydrolyzed and enzymatically treated to produce syrups, particularly high fructose corn syrup, a sweetener; and also fermented and distilled to produce grain alcohol. Grain alcohol from maize is traditionally the source of Bourbon whiskey. Corn flour is used to make cornbread and other baked products.

 

In prehistoric times Mesoamerican women used a metate to process maize into ground cornmeal, allowing the preparation of foods that were more calorie dense than popcorn. After ceramic vessels were invented the Olmec people began to cook maize together with beans, improving the nutritional value of the staple meal. Although maize naturally contains niacin, an important nutrient, it was not bioavailable without the process of nixtamalization. The Maya used nixtamal meal to make varieties of porridges and tamales. The process was later used in the cuisine of the American South to prepare corn for grits and hominy.

 

Maize is a staple of Mexican cuisine. Masa (cornmeal treated with limewater) is the main ingredient for tortillas, atole and many other dishes of Central American food. It is the main ingredient of corn tortilla, tamales, pozole, atole and all the dishes based on them, like tacos, quesadillas, chilaquiles, enchiladas, tostadas and many more. In Mexico the fungus of maize, known as huitlacoche, is considered a delicacy.

 

Coarse maize meal is made into a thick porridge in many cultures: from the polenta of Italy, the angu of Brazil, the mămăligă of Romania, to cornmeal mush in the US (or hominy grits in the South) or the food called mieliepap in South Africa and sadza, nshima, ugali and other names in other parts of Africa. Introduced into Africa by the Portuguese in the 16th century, maize has become Africa's most important staple food crop. These are commonly eaten in the Southeastern United States, foods handed down from Native Americans, who called the dish sagamite.

 

Maize can also be harvested and consumed in the unripe state, when the kernels are fully grown but still soft. Unripe maize must usually be cooked to become palatable; this may be done by simply boiling or roasting the whole ears and eating the kernels right off the cob. Sweet corn, a genetic variety that is high in sugars and low in starch, is usually consumed in the unripe state. Such corn on the cob is a common dish in the United States, Canada, United Kingdom, Cyprus, some parts of South America, and the Balkans, but virtually unheard of in some European countries. Corn on the cob was hawked on the streets of early 19th-century New York City by poor, barefoot "Hot Corn Girls", who were thus the precursors of hot dog carts, churro wagons, and fruit stands seen on the streets of big cities today.

 

Within the United States, the usage of maize for human consumption constitutes only around 1/40th of the amount grown in the country. In the United States and Canada, maize is mostly grown to feed livestock, as forage, silage (made by fermentation of chopped green cornstalks), or grain. Maize meal is also a significant ingredient of some commercial animal food products.

 

NUTRITIONAL VALUE

Raw, yellow, sweet maize kernels are composed of 76% water, 19% carbohydrates, 3% protein, and 1% fat (table). In a 100-gram serving, maize kernels provide 86 calories and are a good source (10–19% of the Daily Value) of the B vitamins, thiamin, niacin (but see Pellagra warning below), pantothenic acid (B5) and folate (right table for raw, uncooked kernels, USDA Nutrient Database). In moderate amounts, they also supply dietary fiber and the essential minerals, magnesium and phosphorus whereas other nutrients are in low amounts (table).

 

Maize has suboptimal amounts of the essential amino acids tryptophan and lysine, which accounts for its lower status as a protein source. However, the proteins of beans and legumes complement those of maize.

 

FEED AND FODDER FOR LIVESTOCK

Maize is a major source of both grain feed and fodder for livestock. It is fed to the livestock in various ways. When it is used as a grain crop, the dried kernels are used as feed. They are often kept on the cob for storage in a corn crib, or they may be shelled off for storage in a grain bin. The farm that consumes the feed may produce it, purchase it on the market, or some of both. When the grain is used for feed, the rest of the plant (the corn stover) can be used later as fodder, bedding (litter), or soil amendment. When the whole maize plant (grain plus stalks and leaves) is used for fodder, it is usually chopped all at once and ensilaged, as digestibility and palatability are higher in the ensilaged form than in the dried form. Maize silage is one of the most valuable forages for ruminants. Before the advent of widespread ensilaging, it was traditional to gather the corn into shocks after harvesting, where it dried further. With or without a subsequent move to the cover of a barn, it was then stored for weeks to several months until fed to the livestock. Today ensilaging can occur not only in siloes but also in silage wrappers. However, in the tropics, maize can be harvested year-round and fed as green forage to the animals.

 

CHEMICALS

Starch from maize can also be made into plastics, fabrics, adhesives, and many other chemical products.

 

The corn steep liquor, a plentiful watery byproduct of maize wet milling process, is widely used in the biochemical industry and research as a culture medium to grow many kinds of microorganisms.

 

Chrysanthemin is found in purple corn and is used as a food coloring.

 

BIO-FUEL

"Feed maize" is being used increasingly for heating; specialized corn stoves (similar to wood stoves) are available and use either feed maize or wood pellets to generate heat. Maize cobs are also used as a biomass fuel source. Maize is relatively cheap and home-heating furnaces have been developed which use maize kernels as a fuel. They feature a large hopper that feeds the uniformly sized maize kernels (or wood pellets or cherry pits) into the fire.[citation needed]

 

Maize is increasingly used as a feedstock for the production of ethanol fuel. When considering where to construct an ethanol plant, one of the site selection criteria is to ensure there is locally available feedstock. Ethanol is mixed with gasoline to decrease the amount of pollutants emitted when used to fuel motor vehicles. High fuel prices in mid-2007 led to higher demand for ethanol, which in turn led to higher prices paid to farmers for maize. This led to the 2007 harvest being one of the most profitable maize crops in modern history for farmers. Because of the relationship between fuel and maize, prices paid for the crop now tend to track the price of oil.

 

The price of food is affected to a certain degree by the use of maize for biofuel production. The cost of transportation, production, and marketing are a large portion (80%) of the price of food in the United States. Higher energy costs affect these costs, especially transportation. The increase in food prices the consumer has been seeing is mainly due to the higher energy cost. The effect of biofuel production on other food crop prices is indirect. Use of maize for biofuel production increases the demand, and therefore price of maize. This, in turn, results in farm acreage being diverted from other food crops to maize production. This reduces the supply of the other food crops and increases their prices.

 

Maize is widely used in Germany as a feedstock for biogas plants. Here the maize is harvested, shredded then placed in silage clamps from which it is fed into the biogas plants. This process makes use of the whole plant rather than simply using the kernels as in the production of fuel ethanol.

 

A biomass gasification power plant in Strem near Güssing, Burgenland, Austria, began in 2005. Research is being done to make diesel out of the biogas by the Fischer Tropsch method.

 

Increasingly, ethanol is being used at low concentrations (10% or less) as an additive in gasoline (gasohol) for motor fuels to increase the octane rating, lower pollutants, and reduce petroleum use (what is nowadays also known as "biofuels" and has been generating an intense debate regarding the human beings' necessity of new sources of energy, on the one hand, and the need to maintain, in regions such as Latin America, the food habits and culture which has been the essence of civilizations such as the one originated in Mesoamerica; the entry, January 2008, of maize among the commercial agreements of NAFTA has increased this debate, considering the bad labor conditions of workers in the fields, and mainly the fact that NAFTA "opened the doors to the import of maize from the United States, where the farmers who grow it receive multimillion-dollar subsidies and other government supports. ... According to OXFAM UK, after NAFTA went into effect, the price of maize in Mexico fell 70% between 1994 and 2001. The number of farm jobs dropped as well: from 8.1 million in 1993 to 6.8 million in 2002. Many of those who found themselves without work were small-scale maize growers."). However, introduction in the northern latitudes of the US of tropical maize for biofuels, and not for human or animal consumption, may potentially alleviate this.

 

COMMODITY

Maize is bought and sold by investors and price speculators as a tradable commodity using corn futures contracts. These "futures" are traded on the Chicago Board of Trade (CBOT) under ticker symbol C. They are delivered every year in March, May, July, September, and December.

 

ORNAMENTAL AND OTHER USES

Some forms of the plant are occasionally grown for ornamental use in the garden. For this purpose, variegated and colored leaf forms as well as those with colorful ears are used.

 

Corncobs can be hollowed out and treated to make inexpensive smoking pipes, first manufactured in the United States in 1869.

 

An unusual use for maize is to create a "corn maze" (or "maize maze") as a tourist attraction. The idea of a maize maze was introduced by the American Maze Company who created a maze in Pennsylvania in 1993. Traditional mazes are most commonly grown using yew hedges, but these take several years to mature. The rapid growth of a field of maize allows a maze to be laid out using GPS at the start of a growing season and for the maize to grow tall enough to obstruct a visitor's line of sight by the start of the summer. In Canada and the US, these are popular in many farming communities.

 

Maize kernels can be used in place of sand in a sandboxlike enclosure for children's play.

 

Stigmas from female maize flowers, popularly called corn silk, are sold as herbal supplements.

 

Maize is used as a fish bait, called "dough balls". It is particularly popular in Europe for coarse fishing.

 

Additionally, feed corn is sometimes used by hunters to bait animals such as deer or wild hogs.

 

UNITED STATES USAGE BREAKDOWN

The breakdown of usage of the 12.1-billion-bushel (307-million-tonne) 2008 US maize crop was as follows, according to the World Agricultural Supply and Demand Estimates Report by the USDA.In the US since 2009/2010, maize feedstock use for ethanol production has somewhat exceeded direct use for livestock feed; maize use for fuel ethanol was 5,130 million bushels (130 million tonnes) in the 2013/2014 marketing year.A fraction of the maize feedstock dry matter used for ethanol production is usefully recovered as DDGS (dried distillers grains with solubles). In the 2010/2011 marketing year, about 29.1 million tonnes of DDGS were fed to US livestock and poultry. Because starch utilization in fermentation for ethanol production leaves other grain constituents more concentrated in the residue, the feed value per kg of DDGS, with regard to ruminant-metabolizable energy and protein, exceeds that of the grain. Feed value for monogastric animals, such as swine and poultry, is somewhat lower than for ruminants.

 

HAZARDS

PELLAGRA

When maize was first introduced into farming systems other than those used by traditional native-American peoples, it was generally welcomed with enthusiasm for its productivity. However, a widespread problem of malnutrition soon arose wherever maize was introduced as a staple food. This was a mystery, since these types of malnutrition were not normally seen among the indigenous Americans, for whom maize was the principal staple food.

 

It was eventually discovered that the indigenous Americans had learned to soak maize in alkali — water (the process now known as nixtamalization) — made with ashes and lime (calcium oxide) since at least 1200–1500 BC by Mesoamericans. They did this to liberate the corn hulls, but (unbeknownst to natives or colonists) it coincidentally liberates the B-vitamin niacin, the lack of which was the underlying cause of the condition known as pellagra.

 

Maize was introduced into the diet of non-indigenous Americans without the necessary cultural knowledge acquired over thousands of years in the Americas. In the late 19th century, pellagra reached epidemic proportions in parts of the southern US, as medical researchers debated two theories for its origin: the deficiency theory (which was eventually shown to be true) said that pellagra was due to a deficiency of some nutrient, and the germ theory said that pellagra was caused by a germ transmitted by stable flies. A third theory, promoted by the eugenicist Charles Davenport, held that people only contracted pellagra if they were susceptible to it due to certain "constitutional, inheritable" traits of the affected individual.

 

Once alkali processing and dietary variety were understood and applied, pellagra disappeared in the developed world. The development of high lysine maize and the promotion of a more balanced diet have also contributed to its demise. Pellagra still exists today in food-poor areas and refugee camps where people survive on donated maize.

 

ALLERGY

Maize contains lipid transfer protein, an indigestible protein that survives cooking. This protein has been linked to a rare and understudied allergy to maize in humans. The allergic reaction can cause skin rash, swelling or itching of mucous membranes, diarrhea, vomiting, asthma and, in severe cases, anaphylaxis. It is unclear how common this allergy is in the general population.

 

MYCOTOXINS

Fungicide application does not reduce fungal growth or mycotoxin dramatically, although it can be a part of a successful reduction strategy. Among the most common toxins are those produced by Aspergillus and Fusarium spp. The most common toxins are aflatoxins, fumonisins, zearalenone, and ochratoxin A. Bt maize discourages insect vectors and by so doing it dramatically reduces concentrations of fumonisins, significantly reduces aflatoxins, but only mildly reduces others.

 

ART

Maize has been an essential crop in the Andes since the pre-Columbian era. The Moche culture from Northern Peru made ceramics from earth, water, and fire. This pottery was a sacred substance, formed in significant shapes and used to represent important themes. Maize was represented anthropomorphically as well as naturally.

 

In the United States, maize ears along with tobacco leaves are carved into the capitals of columns in the United States Capitol building. Maize itself is sometimes used for temporary architectural detailing when the intent is to celebrate the fall season, local agricultural productivity and culture. Bundles of dried maize stalks are often displayed along with pumpkins, gourds and straw in autumnal displays outside homes and businesses. A well-known example of architectural use is the Corn Palace in Mitchell, South Dakota, which uses cobs and ears of colored maize to implement a mural design that is recycled annually. Another well-known example is the Field of Corn sculpture in Dublin, Ohio, where hundreds of concrete ears of corn stand in a grassy field.

 

A maize stalk with two ripe ears is depicted on the reverse of the Croatian 1 lipa coin, minted since 1993.

 

WIKIPEDIA

কালিম । Common Mormon (Papilio polytes) - Male on a mating dance with a female (Form: romulus)

 

A common species of swallowtail butterfly (family: papilionidae) widely distributed across Asia. Seen round the year throughout India from plains up to 2000m. This butterfly is known for the mimicry displayed by the numerous polymorphic forms of its females. These are as follows: cyrus, stichius, romulus.

 

Host Plant: Ixora coccinea; Rangan (রঙ্গন, Rugmini in Hindi, commonly known as the Jungle Geranium, Flame of the Woods, and Jungle Flame from Rubiaceae family) is an exotic bright red flower, bloom as a flower bunch comprises of lot of small red flowers at the top of branch. Each red flower has four petals and holds four yellow stamen(no filament) between the petals. Flower blooms more or less throughout the year, but best during the rainy season.

 

Tajpur Sea Beach, Bay of Bengal

Monsoon Images of Bengal, India

 

Sigma 150-600mm 5-6.3 DG HSM OS Contemporary plus Nikon D7000

   

কালিম । Common Mormon (Papilio polytes) - Male

 

A common species of swallowtail butterfly (family: papilionidae) widely distributed across Asia. Seen round the year throughout India from plains up to 2000m. This butterfly is known for the mimicry displayed by the numerous polymorphic forms of its females. These are as follows: cyrus, stichius, romulus.

 

Host Plant: Ixora coccinea; Rangan (রঙ্গন, Rugmini in Hindi, commonly known as the Jungle Geranium, Flame of the Woods, and Jungle Flame from Rubiaceae family) is an exotic bright red flower, bloom as a flower bunch comprises of lot of small red flowers at the top of branch. Each red flower has four petals and holds four yellow stamen(no filament) between the petals. Flower blooms more or less throughout the year, but best during the rainy season.

 

Tajpur Sea Beach, Bay of Bengal

Monsoon Images of Bengal, India

 

Sigma 150-600mm 5-6.3 DG HSM OS Contemporary plus Nikon D7000

 

The Elbe Sandstone Mountains,[1] also called the Elbe sandstone highlands[2] (Czech: Labské pískovce; German: Elbsandsteingebirge) is a mountain range straddling the border between the state of Saxony in southeastern Germany and the North Bohemian region of the Czech Republic, with about three-quarters of the area lying on the German side. The mountains are also referred to as Saxon Switzerland and Bohemian Switzerland in both German and Czech (Sächsische Schweiz and Böhmische Schweiz in German, Saské Švýcarsko and České Švýcarsko in Czech) or simply combined as Saxon-Bohemian Switzerland.[3] In both countries, the mountain range has been declared a national park. The name derives from the sandstone which was carved by erosion. The river Elbe breaks through the mountain range in a steep and narrow valley.The Elbe Sandstone Mountains extend on both sides of the Elbe from the Saxon town of Pirna in the northwest toward Bohemian Děčín in the southeast. Their highest peak with 723 m (2,372 ft) is the Děčínský Sněžník in Bohemian Switzerland on the left bank of the river in Bohemian Switzerland north of Děčín. The mountain range links the Ore Mountains in the west with the Lusatian Highlands range of the Sudetes in the east. Saxon Switzerland and the Zittau Mountains of the Lusatian Mountains form the Saxon-Bohemian Chalk Sandstone Region.

     

The Elbe valley in Bohemian Switzerland. The mountains on the horizon lie in Saxony

[edit] Terrain

 

The most striking characteristic of this deeply dissected rocky mountain range is the extraordinary variety of terrain within the smallest area. Unique amongst the Central European Uplands are the constant changes between plains, ravines, table mountains and rocky regions with undeveloped areas of forest. This diversity is ecologically significant. The variety of different locations, each with its own conditions in terms of soil and microclimate, has produced an enormous richness of species. The numbers of ferns and mosses alone is unmatched by any other of the German central uplands.

 

The occurrence of Elbe sandstones and hence the Elbe Sandstone Mountains themselves is related to widespread deposition by a former sea in the Upper Cretaceous epoch. On the Saxon side of the border the term "Elbe Valley Cretaceous" (Elbtalkreide) is used, referring to a region stretching from Meißen-Oberau in the northwest through Dresden and Pirna into Saxon Switzerland, and which is formed by sandstones, planers and other rocks as well as basal conglomerates (Grundschottern or Basalkonglomerate) of older origin. Several erosion relics from Reinhardtsgrimma through Dippoldiswalde and the Tharandt Forest to Siebenlehn form isolated examples south of Dresden. They are mainly characterised by sandstones.

On the Bohemian side the sandstone beds continue and form part of the North Bohemian Cretaceous (Nordböhmische Kreide). The chalk sediments of the Zittau Basin are counted as part of the latter due to their regional-geological relationships. The sedimentary sequences of the Cretaceous sea continue across a wide area of the Czech Republic to Moravia. Together these beds form the Saxon-Bohemian Cretaceous Zone. In Czech geological circles, the Elbe Valley Cretaceous is described as the foothills of the Bohemian Cretaceous Basin[3] (Böhmischen Kreidebecken).

 

[edit] Geology

     

Hercules pillars in the Biela valley

The eroded sandstone landscape of this region was formed from depositions that accumulated on the bottom of the sea millions of years ago. Large rivers carried sand and other eroded debris into the Cretaceous sea. Rough quartz sand, clay and fine marl sank and became lithified layer by layer. A compact sandstone sequence developed, about 20 x 30 kilometres wide and up to 600 metres thick dating to the lower Cenomanian to Santonian stages.[3] The tremendous variety of shapes in the sandstone landscape is a result of the subsequent chemical and physical erosion and biological processes acting on the rocks formed from those sands laid down during the Cretaceous Period.

 

The inlets of a Cretaceous sea, together with marine currents, carried away sand over a very long period of time into a shallow zone of the sea and then the diagenetic processes at differing pressure regimes resulted in the formation of sandstone beds. Its stratification is characterized by variations in the horizontal structure (deposits of clay minerals, grain sizes of quartz, differences in the grain-cement) as well as a typical but fairly small fossil presence and variably porous strata.

 

After the Cretaceous sea had retreated (marine regression), the surface of the land was shaped by weathering influences and watercourses, of which the Elbe made the deepest incision. Later the Lusatian granodiorite was uplifted over the 600 metre thick sandstone slab along the Lusatian Fault and pushed it downwards until it fractured. This northern boundary of the sandstone deposit lies roughly along the line Pillnitz–Hohnstein–Hinterhermsdorf–Krásná Lípa (Schönlinde).

     

Crags near Rathen

In the Tertiary period, the adjacent region of the Central Bohemian Uplands and the Lusatian Mountains was shaped and affected by intense volcanism; but individual intrusions of magma also forced their way through the sandstone platform of the Elbe Sandstone Mountains. The most striking evidence of this phase in the earth's history are the conical basaltic hills of Růžovský vrch (Rosenberg), Cottaer Spitzberg and Raumberg, but also Großer and Kleiner Winterberg.

 

At its southwestern edge the sandstone plate was uplifted by over 200 metres at the Karsdorf Fault, whereby the slab was tilted even more and increased the gradient of the Elbe River. The water masses cut valleys into the rock with their streambeds and contributed in places to the formation of the rock faces. Over time the gradients reduced, the streambed of the Elbe widened out and changed its course time and again, partly as a result of the climatic influences of the ice ages.

 

The mineral composition of the sandstone beds has a direct effect on the morphology of the terrain. The fine-grained form with clayey-silty cement between the quartz grains causes banks and slopes with terracing. The beds of sandstone with siliceous cement are typically the basis of the formation of rock faces and crags. Small variations in the cement composition of the rock can have a visible impact on the landscape.[4]

 

Elbe Sandstone gets its characteristic cuboid appearance from its thick horizontal strata (massive bedding) and its vertical fissures. In 1839 Bernhard Cotta wrote about this in his comments on the geognostic map: "Vertical fissures and cracks cut through, often virtually at right angles, the horizontal layers and, as a result, parallelepiped bodies are formed, that have given rise to the description Quader Sandstone."[5]. Quader is German for an ashlar or block of stone, hence the name "Square Sandstone" is also used in English.[6]

 

The term quader sandstone mountains or square sandstone mountains (Quadersandsteingebirge), introduced by Hanns Bruno Geinitz in 1849, is an historic, geological term for similar sandstone deposits, but was also used in connexion with the Elbe Sandstone Mountains.[7][8].

     

Honeycomb weathering

The fissures were formed as a result of long-term tectonic stresses on the entire sandstone platform of the mountain range. This network of clefts runs through the sandstone beds in a relatively regular way, but in different directions in two regions of the range.[9] Subsequent weathering processes of very different forms and simultaneous complex deposition (leaching, frost and salt wedging, wind, solution weathering with sintering as well as biogenic and microbial effects) have further changed the nature of the rock surface. For example, collapse caves, small hole-like cavities (honeycomb weathering) with hourglass-shaped pillars (Sanduhr), chimneys, crevices and mighty, rugged rock faces.

  

Many morphological formations in the rocky landscape of the Elbe Sandstone Mountains are suspected to have been formed as a consequence of karstification. Important indicators of such processes in the polygenetic and polymorphic erosion landscape of the Elbe Sandstone Mountains are the furrows with parallel ridges between them (grykes and clints) that look like cart ruts and which are particularly common, as well as extensive cave systems. They are occasionally described by the term pseudokarst. The application of the concept to several erosion formations in the sandstone of this mountain range is however contentious.[10][11][12][13][14] Czech geologists have identified in quarzite-cemented sandstone areas in the northern part of the Bohemian Cretaceous Basin, karst features in the shape of spherical caverns and cave formations. According to them, these emerged as a result of solution processes by water in complex interactions with iron compounds from neighbouring or intrusive magmatic-volcanic rocks. The variation in relief in these sandstone regions is explained on the basis of these processes.[15][16] The Elbe Sandstone Mountains are the greatest cretaceous sandstone erosion complex in Europe.[17]

 

Human-induced changes caused by nearly 1,000 years of continual sandstone quarrying have also contributed in parts of the sandstone highlands to the appearance of the landscape today. The fissures (called Loose by the quarrymen) played an important role here, because they provided in effect natural divisions in the rock that were helpful when demolishing a rock face or when dressing the rough blocks of stone.[18]

 

The sandstone of this region is a sought-after building material used for example, for imposing city edifices such as the Church of Our Lady in Dresden.

  

Das Elbsandsteingebirge (tschechisch Labské pískovce bzw. Labské pískovcové pohoří) ist ein vorwiegend aus Sandstein aufgebautes Mittelgebirge am Oberlauf der Elbe in Sachsen (Deutschland) und Nordböhmen (Tschechien). Es ist etwa 700 km² groß und erreicht Höhen bis 723 Meter über dem Meeresspiegel. Der deutsche Teil wird im allgemeinen als Sächsische Schweiz, der tschechische als Böhmische Schweiz (České Švýcarsko) bezeichnet. Der heute häufiger gebrauchte Begriff „Sächsisch-Böhmische Schweiz“ (Českosaské Švýcarsko) ist davon abgeleitet.

  

Das Elbsandsteingebirge erstreckt sich beiderseits der Elbe zwischen der tschechischen Stadt Děčín (Tetschen-Bodenbach) und dem sächsischen Pirna. Die östliche Grenze befindet sich etwa entlang einer Linie zwischen Pirna, Hohnstein, Sebnitz, Chřibská, Česká Kamenice nach Děčín. Die westliche Begrenzung folgt von Pirna etwa dem Tal der Gottleuba zum Erzgebirgskamm und dann entlang des Jílovský potok (Eulaubach) nach Děčín. Der höchste Berg des Gebirges ist mit 723 Metern der Děčínský Sněžník (Hoher Schneeberg) im tschechischen Teil des Gebirges, die höchste deutsche Erhebung ist der Große Zschirnstein (561 m).

 

Im Elbsandsteingebirge befinden sich die Nationalparke Sächsische Schweiz und Böhmische Schweiz.

 

Allgemeines [Bearbeiten]

     

Basteibrücke bei Rathen

Das Charakteristische dieses stark zerklüfteten Felsengebirges ist sein außerordentlicher Formenreichtum auf engstem Raum. Einmalig unter den mitteleuropäischen Mittelgebirgen ist der ökologisch bedeutsame ständige Wechsel von Ebenen, Schluchten, Tafelbergen und Felsrevieren mit erhalten gebliebenen geschlossenen Waldbereichen. Die Vielfalt der unterschiedlichen Standorte mit jeweils eigenen Verhältnissen in Bezug auf Boden und Mikroklima haben eine enorme Artenvielfalt hervorgebracht. Allein die Vielfalt der vorkommenden Farne und Moose wird von keiner anderen deutschen Mittelgebirgslandschaft erreicht.

 

Das Auftreten des Elbsandsteins und damit des Elbsandsteingebirges steht im Zusammenhang mit den großräumigen Ablagerungen eines ehemaligen Meeres in der Oberkreide. Auf sächsischer Seite spricht man von der Elbtalkreide, die sich auf einem Gebiet zwischen Meißen-Oberau im Nordwesten über Dresden und Pirna bis in die Sächsische Schweiz erstreckt und in Form von Sandsteinen, Plänern und weiteren Gesteinen sowie an ihrer Basis mit Grundschottern (Basalkonglomerate) älterer Herkunft auftritt. Einige Erosionsrelikte zwischen Reinhardtsgrimma über Dippoldiswalde und Tharandter Wald bis Siebenlehn bilden südlich von Dresden isolierte Vorkommen. Sie sind hauptsächlich durch Sandsteine gekennzeichnet.

Auf böhmischer Seite setzten sich die Sandsteinablagerungen fort und stellen ein Teil der Nordböhmische Kreide dar. Die Kreidesedimente des Zittauer Beckens werden auf Grund ihrer regionalgeologischen Zusammenhänge der Nordböhmischen Kreide zugeordnet. Die Sedimentabfolgen aus dem Kreidemeer lassen sich in weiteren Landschaftsräumen Tschechiens bis nach Mähren verfolgen. Zusammen bilden diese Ablagerungen die Sächsisch-Böhmische Kreidezone. In der tschechischen Geologie wird die Elbtalkreide als ein Ausläufer des Böhmischen Kreidebeckens beschrieben.

 

Geologie [Bearbeiten]

     

Herkulessäulen im Bielatal

Der mannigfaltige Formenreichtum der Sandsteinlandschaft ist eine Folge chemisch-physikalischer Erosion und biologischer Prozesse von Gesteinen, die aus den in der Kreidezeit abgelagerten Sanden gebildet wurden.

 

Die Zuflüsse eines kreidezeitlichen Meeres und marine Strömungen transportierten über große Zeiträume hinweg in eine Flachmeerzone Sand, welcher über diagenetische Prozesse bei verschiedenen Druckregimen zur Ausbildung von Sandsteinschichten führte. Seine Schichtung ist durch wechselnde horizontale Strukturunterschiede (Einlagerungen von Tonmineralen, Korngrößen des Quarzes, Unterschiede in der Kornbindung) sowie eine typische aber überwiegend geringe Fossilführung sowie mehr oder weniger wasserführende Schichten charakterisiert.

 

Nachdem sich das kreidezeitliche Meer zurückgezogen (Regression) hatte, formten Verwitterungseinflüsse und Wasserläufe die Oberfläche, von denen die Elbe den stärksten Einschnitt erzeugte. Entlang der Lausitzer Verwerfung schob sich später im Norden der Lausitzer Granodiorit auf die etwa 600 Meter mächtige Sandsteinplatte und drückte diese nach unten, bis sie brach. Dieser Nordrand des Sandsteinvorkommens liegt ungefähr auf der Linie Pillnitz–Hohnstein–Hinterhermsdorf–Krásná Lípa (Schönlinde).

     

Wabenverwitterung

Im Tertiär wurde vor allem das angrenzende Gebiet des Böhmischen Mittelgebirges und des Lausitzer Gebirges durch einen intensiven Vulkanismus geformt und beeinflusst, einzelne Magmaintrusionen durchstießen aber auch die Sandsteintafel des Elbsandsteingebirges. Die markantesten Zeugnisse dieser erdgeschichtlichen Phase sind vor allem die basaltischen Kegelberge Růžovský vrch (Rosenberg), Cottaer Spitzberg und Raumberg, aber auch Großer und Kleiner Winterberg.

 

Am Südwestrand wurde die Sandsteinplatte an der Karsdorfer Störung um über 200 Meter angehoben, wodurch die Platte noch stärker kippte und sich das Gefälle des Elbestroms verstärkte. Die Wassermassen gruben mit ihrem Flussbett Täler in das Gestein und trugen stellenweise zur Bildung der Felswände bei. Mit der Zeit verminderte sich das Gefälle; das Flussbett des Elbestroms verbreiterte sich und wechselte immer wieder, auch durch eiszeitliche Klimaeinflüsse bedingt, seinen Verlauf.

 

Die mineralische Zusammensetzung der Sandsteinablagerungen hat unmittelbare Auswirkungen auf die Morphologie des Geländes. Der feinkörnige Typus mit tonig-schluffiger Bindung zwischen den Quarzkörnen verursacht Böschungen und Hänge mit Terrassierung. Die kieselig gebundenen Sandsteinbänke sind für die Ausbildung von Wänden und Klippen typisch. Geringe Schwankungen bei der Bindemittelzusammensetzung im Gestein können sich im Landschaftsbild sichtbar auswirken.[1]

 

Seine charakteristische Quader-Erscheinungsweise verdankt der Elbsandstein einer weitständigen horizontalen Schichtung (Bankung) und der vertikalen Zerklüftung. Bernhard Cotta schreibt 1839 in seinen Erläuterungen zur geognostischen Karte hierzu: „Verticale Klüfte und Spalten durchschneiden, unter sich ziemlich rechtwinkelig, die wagerechten Schichten, und dadurch entsteht jene Absonderung in parallelepipedische Körper, die zu dem Namen Quadersandstein Veranlassung gegeben hat.“[2]

 

Der Begriff Quadersandsteingebirge, von Hanns Bruno Geinitz 1849 eingeführt, ist ein historischer geologischer Terminus für vergleichbare Sandsteinablagerungen, wurde jedoch auch im Zusammenhang mit dem Elbsandsteingebirge verwendet.[3][4].

 

Die Klüfte bildeten sich durch lang anhaltende tektonische Beanspruchungen der gesamten Sandsteinplatte des Gebirges. Dieses Kluftnetz durchzieht, in zwei Bereichen des Gebirges mit unterschiedlichen Richtungen, in relativ regelmäßiger Form diese Sandsteinablagerungen.[5] Nachfolgend einsetzende Verwitterungsvorgänge sehr unterschiedlicher Art und gegenseitiger komplexer Überlagerung (Auswaschungen, Frost- und Salzsprengungen, Wind, Lösungsvorgänge mit Versinterungen sowie biogene und mikrobielle Einwirkungen) haben die Felsoberflächen weiter geprägt. Es entstanden beispielsweise Einsturzhöhlen, kleine lochähnliche Vertiefungen (Alveolen) mit Sanduhren, Kamine, Spalten und schroffe mächtige Wände.

Vielfältige morphologische Ausbildungen in der Felsenlandschaft des Elbsandsteingebirges werden hinsichtlich ihrer Entstehung als Folge einer Verkarstung diskutiert. Besonders häufig auftretende Furchen mit parallelen Kämmen, sie muten wie Karrenstrukturen an, sowie umfassende Höhlensysteme bieten in der polygenetischen und polymorphen Erosionslandschaft des Elbsandsteingebirges hierzu wichtige Anhaltspunkte. Sie werden gelegentlich mit dem Begriff Pseudokarst bezeichnet. Die Übertragung des Begriffs auf einige Erosionsformen im Sandstein des Elbsandsteingebirges und die daraus abgeleitete Erklärungsweise sind jedoch umstritten.[6][7][8][9][10] Tschechische Geologen konstatieren für quarzitisch gebundene Sandsteinbereiche im nördlichen Teil des Böhmischen Kreidebeckens Karsterscheinungen in Form von sphärischen Hohlräumen und Höhlenbildungen. Sie entstanden demnach durch Lösungsvorgänge von Wasser im komplexen Zusammenspiel mit Eisenverbindungen aus benachbarten bzw. intrudierten magmatisch-vulkanischen Gesteinen. Auf der Grundlage dieser Prozesse wird die Variantenvielfalt des Reliefs in jenen Sandsteingebieten erklärt.[11][12] Das Elbsandsteingebirge ist der größte Kreidesandsteinerosionskomplex in Europa.[13]

 

Die anthropogen verursachten Veränderungen durch den rund 1000 Jahre anhaltenden Sandsteinabbau trugen in Teilbereichen des Elbsandsteingebirges zusätzlich zur Formung des heute vorhandenen Landschaftsbildes bei. Dabei spielten die Klüfte (von den Steinbrechern Loose genannt) eine wichtige Rolle, da sie eine natürliche Begrenzung bei der Wandfällung und Rohblockzurichtung hilfreich vorgaben.[14]

  

More info and other languages available at:

 

de.wikipedia.org/wiki/Elbsandsteingebirge

For the Elysee Palace in Paris, with the request of President Georges Pompidou, Yacacov Agam created in 1972 a whole environmental of the Salon with the walls covered with polymorphic murals of changing images a kinetic ceiling, moving transparent colored doors and a kinetic carpet on which he placed a sculpture. It embraces viewers: they are no longer looking at a framed, fixed scene, but rather arc moving within an artistic space which changes constantly according to their shifting position and point of view. Similar attempt was made for the concert hall, Forum Leverkusen in Germany in 1970.

 

This photo was taken in Pompidou Center, Paris

 

(20110820-120040-3450-1000d-a1)

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Es una especie muy polimorfa, que se extiende desde el Himalaya hasta Japón, Assam, centro norte de China, Himalaya occidental y oriental, Japón, Corea, Laos, Myanmar, Nepal, Taiwan, Tibet, Vietnam, West Himalaya. los ejemplares representados aquí fueron recolectados en Yunna en 1998 por Allen Coombes como Quercus pentacycla (CMBS 516). En iturraran se encuentran en la zona 3.

 

t is a highly polymorphic species, ranging from the Himalayas to Japan, Assam, North-Central China, Western and Eastern Himalayas, Japan, Korea, Laos, Myanmar, Nepal, Taiwan, Tibet, Vietnam, West Himalayas. the specimens represented here were collected in Yunna in 1998 by Allen Coombes as Quercus pentacycla (CMBS 516). In iturraran they are in area 3.

Maize (/meɪz/ MAYZ; Zea mays subsp. mays, from Spanish: maíz after Taino: mahiz), also known as corn (North American and Australian English), is a cereal grain first domesticated by indigenous peoples in southern Mexico about 10,000 years ago. The leafy stalk of the plant produces pollen inflorescences and separate ovuliferous inflorescences called ears that yield kernels or seeds, which are fruits.

 

Maize has become a staple food in many parts of the world, with the total production of maize surpassing that of wheat or rice. In addition to being consumed directly by humans (often in the form of masa), maize is also used for corn ethanol, animal feed and other maize products, such as corn starch and corn syrup. The six major types of maize are dent corn, flint corn, pod corn, popcorn, flour corn, and sweet corn.[5] Sugar-rich varieties called sweet corn are usually grown for human consumption as kernels, while field corn varieties are used for animal feed, various corn-based human food uses (including grinding into cornmeal or masa, pressing into corn oil, and fermentation and distillation into alcoholic beverages like bourbon whiskey), and as chemical feedstocks. Maize is also used in making ethanol and other biofuels.

 

Maize is widely cultivated throughout the world, and a greater weight of maize is produced each year than any other grain. In 2014, total world production was 1.04 billion tonnes. Maize is the most widely grown grain crop throughout the Americas, with 361 million metric tons grown in the United States alone in 2014. Genetically modified maize made up 85% of the maize planted in the United States in 2009. Subsidies in the United States help to account for its high level of cultivation of maize and its position as the largest producer in the world.

 

HISTORY

PRE-COLUMBIAN DEVELOPMENT

Maize is a cultigen; human intervention is required for it to propagate. Whether or not the kernels fall off the cob on their own is a key piece of evidence used in archaeology to distinguish domesticated maize from its naturally-propagating teosinte ancestor. Genetic evidence can also be used to determine when various lineages split.

 

Most historians believe maize was domesticated in the Tehuacán Valley of Mexico. Recent research in the early 21st century has modified this view somewhat; scholars now indicate the adjacent Balsas River Valley of south-central Mexico as the center of domestication.

 

An influential 2002 study by Matsuoka et al. has demonstrated that, rather than the multiple independent domestications model, all maize arose from a single domestication in southern Mexico about 9,000 years ago. The study also demonstrated that the oldest surviving maize types are those of the Mexican highlands. Later, maize spread from this region over the Americas along two major paths. This is consistent with a model based on the archaeological record suggesting that maize diversified in the highlands of Mexico before spreading to the lowlands.

 

Archaeologist Dolores Piperno has said:

 

A large corpus of data indicates that [maize] was dispersed into lower Central America by 7600 BP [5600 BC] and had moved into the inter-Andean valleys of Colombia between 7000 and 6000 BP [5000–4000 BC].

— Dolores Piperno, The Origins of Plant Cultivation and Domestication in the New World Tropics: Patterns, Process, and New Developments

 

Since then, even earlier dates have been published.

 

According to a genetic study by Embrapa, corn cultivation was introduced in South America from Mexico, in two great waves: the first, more than 6000 years ago, spread through the Andes. Evidence of cultivation in Peru has been found dating to about 6700 years ago. The second wave, about 2000 years ago, through the lowlands of South America.

 

The earliest maize plants grew only small, 25-millimetre-long (1 in) corn cobs, and only one per plant. In Jackson Spielvogel's view, many centuries of artificial selection (rather than the current view that maize was exploited by interplanting with teosinte) by the indigenous people of the Americas resulted in the development of maize plants capable of growing several cobs per plant, which were usually several centimetres/inches long each. The Olmec and Maya cultivated maize in numerous varieties throughout Mesoamerica; they cooked, ground and processed it through nixtamalization. It was believed that beginning about 2500 BC, the crop spread through much of the Americas. Research of the 21st century has established even earlier dates. The region developed a trade network based on surplus and varieties of maize crops.

 

Mapuches of south-central Chile cultivated maize along with quinoa and potatoes in pre-Hispanic times; however, potato was the staple food of most Mapuches, "specially in the southern and coastal [Mapuche] territories where maize did not reach maturity". Before the expansion of the Inca Empire maize was traded and transported as far south as 40°19' S in Melinquina, Lácar Department. In that location maize remains were found inside pottery dated to 730 ± 80 BP and 920 ± 60 BP. Probably this maize was brought across the Andes from Chile. The presence of maize in Guaitecas Archipelago (43°55' S), the southernmost outpost of pre-Hispanic agriculture, is reported by early Spanish explorers. However the Spanish may have misidentified the plant.

 

COLUMBIAN EXCHANGE

After the arrival of Europeans in 1492, Spanish settlers consumed maize, and explorers and traders carried it back to Europe and introduced it to other countries. Spanish settlers far preferred wheat bread to maize, cassava, or potatoes. Maize flour could not be substituted for wheat for communion bread, since in Christian belief only wheat could undergo transubstantiation and be transformed into the body of Christ. Some Spaniards worried that by eating indigenous foods, which they did not consider nutritious, they would weaken and risk turning into Indians. "In the view of Europeans, it was the food they ate, even more than the environment in which they lived, that gave Amerindians and Spaniards both their distinctive physical characteristics and their characteristic personalities." Despite these worries, Spaniards did consume maize. Archeological evidence from Florida sites indicate they cultivated it as well.

 

Maize spread to the rest of the world because of its ability to grow in diverse climates. It was cultivated in Spain just a few decades after Columbus's voyages and then spread to Italy, West Africa and elsewhere. Widespread cultivation most likely began in southern Spain in 1525, after which it quickly spread to the rest of the Spanish Empire including its territories in Italy (and, from there, to other Italian states). Maize had many advantages over wheat and barley; it yielded two and a half times the food energy per unit cultivated area, could be harvested in successive years from the same plot of land, and grew in wildly varying altitudes and climates, from relatively dry regions with only 250 mm (10 in) of annual rainfall to damp regions with over 5,000 mm (200 in). By the 17th century it was a common peasant food in Southwestern Europe, including Portugal, Spain, southern France, and Italy. By the 18th century, it was the chief food of the southern French and Italian peasantry, especially in the form of polenta in Italy.

Names

 

The word maize derives from the Spanish form of the indigenous Taíno word for the plant, mahiz. It is known by other names around the world.

 

The word "corn" outside the US, Canada, Australia, and New Zealand refers to any cereal crop, its meaning understood to vary geographically to refer to the local staple. In the United States,[30] Canada, Australia, and New Zealand, corn primarily means maize; this usage started as a shortening of "Indian corn". "Indian corn" primarily means maize (the staple grain of indigenous Americans), but can refer more specifically to multicolored "flint corn" used for decoration.

 

In places outside the US, Canada, Australia, and New Zealand, corn often refers to maize in culinary contexts. The narrower meaning is usually indicated by some additional word, as in sweet corn, sweetcorn, corn on the cob, baby corn, the puffed confection known as popcorn and the breakfast cereal known as corn flakes.

 

In Southern Africa, maize is commonly called mielie (Afrikaans) or mealie (English), words derived from the Portuguese word for maize, milho.

 

Maize is preferred in formal, scientific, and international usage because it refers specifically to this one grain, unlike corn, which has a complex variety of meanings that vary by context and geographic region. Maize is used by agricultural bodies and research institutes such as the FAO and CSIRO. National agricultural and industry associations often include the word maize in their name even in English-speaking countries where the local, informal word is something other than maize; for example, the Maize Association of Australia, the Indian Maize Development Association, the Kenya Maize Consortium and Maize Breeders Network, the National Maize Association of Nigeria, the Zimbabwe Seed Maize Association.

 

STRUCTURE AND PHYSIOLOGY

The maize plant is often 3 m (10 ft) in height, though some natural strains can grow 13 m (43 ft). The stem is commonly composed of 20 internodes of 18 cm (7 in) length. The leaves arise from the nodes, alternately on opposite sides on the stalk. A leaf, which grows from each node, is generally 9 cm (3+1⁄2 in) in width and 120 cm (3 ft 11 in) in length.

 

Ears develop above a few of the leaves in the midsection of the plant, between the stem and leaf sheath, elongating by around 3 mm (1⁄8 in) per day, to a length of 18 cm (7 in) with 60 cm (24 in) being the maximum alleged in the subspecies. They are female inflorescences, tightly enveloped by several layers of ear leaves commonly called husks. Certain varieties of maize have been bred to produce many additional developed ears. These are the source of the "baby corn" used as a vegetable in Asian cuisine.

 

The apex of the stem ends in the tassel, an inflorescence of male flowers. When the tassel is mature and conditions are suitably warm and dry, anthers on the tassel dehisce and release pollen. Maize pollen is anemophilous (dispersed by wind), and because of its large settling velocity, most pollen falls within a few meters of the tassel.

 

Elongated stigmas, called silks, emerge from the whorl of husk leaves at the end of the ear. They are often pale yellow and 18 cm (7 in) in length, like tufts of hair in appearance. At the end of each is a carpel, which may develop into a "kernel" if fertilized by a pollen grain. The pericarp of the fruit is fused with the seed coat referred to as "caryopsis", typical of the grasses, and the entire kernel is often referred to as the "seed". The cob is close to a multiple fruit in structure, except that the individual fruits (the kernels) never fuse into a single mass. The grains are about the size of peas, and adhere in regular rows around a white, pithy substance, which forms the ear. The maximum size of kernels is reputedly 2.5 cm (1 in). An ear commonly holds 600 kernels. They are of various colors: blackish, bluish-gray, purple, green, red, white and yellow. When ground into flour, maize yields more flour with much less bran than wheat does. It lacks the protein gluten of wheat and, therefore, makes baked goods with poor rising capability. A genetic variant that accumulates more sugar and less starch in the ear is consumed as a vegetable and is called sweet corn. Young ears can be consumed raw, with the cob and silk, but as the plant matures (usually during the summer months), the cob becomes tougher and the silk dries to inedibility. By the end of the growing season, the kernels dry out and become difficult to chew without cooking them tender first in boiling water.

 

Planting density affects multiple aspects of maize. Modern farming techniques in developed countries usually rely on dense planting, which produces one ear per stalk. Stands of silage maize are yet denser,[citation needed] and achieve a lower percentage of ears and more plant matter.

 

Maize is a facultative short-day plant and flowers in a certain number of growing degree days > 10 °C (50 °F) in the environment to which it is adapted. The magnitude of the influence that long nights have on the number of days that must pass before maize flowers is genetically prescribed and regulated by the phytochrome system.

Photoperiodicity can be eccentric in tropical cultivars such that the long days characteristic of higher latitudes allow the plants to grow so tall that they do not have enough time to produce seed before being killed by frost. These attributes, however, may prove useful in using tropical maize for biofuels.

 

Immature maize shoots accumulate a powerful antibiotic substance, 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA). DIMBOA is a member of a group of hydroxamic acids (also known as benzoxazinoids) that serve as a natural defense against a wide range of pests, including insects, pathogenic fungi and bacteria. DIMBOA is also found in related grasses, particularly wheat. A maize mutant (bx) lacking DIMBOA is highly susceptible to attack by aphids and fungi. DIMBOA is also responsible for the relative resistance of immature maize to the European corn borer (family Crambidae). As maize matures, DIMBOA levels and resistance to the corn borer decline.

 

Because of its shallow roots, maize is susceptible to droughts, intolerant of nutrient-deficient soils, and prone to be uprooted by severe winds.

 

While yellow maizes derive their color from lutein and zeaxanthin, in red-colored maizes, the kernel coloration is due to anthocyanins and phlobaphenes. These latter substances are synthesized in the flavonoids synthetic pathway from polymerization of flavan-4-ols by the expression of maize pericarp color1 (p1) gene which encodes an R2R3 myb-like transcriptional activator of the A1 gene encoding for the dihydroflavonol 4-reductase (reducing dihydroflavonols into flavan-4-ols) while another gene (Suppressor of Pericarp Pigmentation 1 or SPP1) acts as a suppressor. The p1 gene encodes an Myb-homologous transcriptional activator of genes required for biosynthesis of red phlobaphene pigments, while the P1-wr allele specifies colorless kernel pericarp and red cobs, and unstable factor for orange1 (Ufo1) modifies P1-wr expression to confer pigmentation in kernel pericarp, as well as vegetative tissues, which normally do not accumulate significant amounts of phlobaphene pigments. The maize P gene encodes a Myb homolog that recognizes the sequence CCT/AACC, in sharp contrast with the C/TAACGG bound by vertebrate Myb proteins.

 

The ear leaf is the leaf most closely associated with a particular developing ear. This leaf and above contribute 70%[57] to 75% to 90% of grain fill. Therefore fungicide application is most important in that region in most disease environments.

 

ABNORMAL FLOWERS

Maize flowers may sometimes exhibit mutations that lead to the formation of female flowers in the tassel. These mutations, ts4 and Ts6, prohibit the development of the stamen while simultaneously promoting pistil development. This may cause inflorescences containing both male and female flowers, or hermaphrodite flowers.

 

GENETICS

Maize is an annual grass in the family Gramineae, which includes such plants as wheat, rye, barley, rice, sorghum, and sugarcane. There are two major species of the genus Zea (out of six total): Zea mays (maize) and Zea diploperennis, which is a perennial type of teosinte. The annual teosinte variety called Zea mays mexicana is the closest botanical relative to maize. It still grows in the wild as an annual in Mexico and Guatemala.

 

Many forms of maize are used for food, sometimes classified as various subspecies related to the amount of starch each has:

 

Flour corn: Zea mays var. amylacea

Popcorn: Zea mays var. everta

Dent corn : Zea mays var. indentata

Flint corn: Zea mays var. indurata

Sweet corn: Zea mays var. saccharata and Zea mays var. rugosa

Waxy corn: Zea mays var. ceratina

Amylomaize: Zea mays

Pod corn: Zea mays var. tunicata Larrañaga ex A. St. Hil.

Striped maize: Zea mays var. japonica

 

This system has been replaced (though not entirely displaced) over the last 60 years by multivariable classifications based on ever more data. Agronomic data were supplemented by botanical traits for a robust initial classification, then genetic, cytological, protein and DNA evidence was added. Now, the categories are forms (little used), races, racial complexes, and recently branches.

 

Maize is a diploid with 20 chromosomes (n=10). The combined length of the chromosomes is 1500 cM. Some of the maize chromosomes have what are known as "chromosomal knobs": highly repetitive heterochromatic domains that stain darkly. Individual knobs are polymorphic among strains of both maize and teosinte.

 

Barbara McClintock used these knob markers to validate her transposon theory of "jumping genes", for which she won the 1983 Nobel Prize in Physiology or Medicine. Maize is still an important model organism for genetics and developmental biology today.

 

The centromeres have two types of structural components, both of which are found only in the centromeres: Large arrays of CentC, a short satellite DNA; and a few of a family of retrotransposons. The B chromosome, unlike the others, contains an additional repeat which extends into neighboring areas of the chromosome. Centromeres can accidentally shrink during division and still function, although it is thought this will fail if it shrinks below a few hundred kilobase. Kinetochores contain RNA originating from centromeres. Centromere regions can become inactive, and can continue in that state if the chromosome still has another active one.

 

The Maize Genetics Cooperation Stock Center, funded by the USDA Agricultural Research Service and located in the Department of Crop Sciences at the University of Illinois at Urbana-Champaign, is a stock center of maize mutants. The total collection has nearly 80,000 samples. The bulk of the collection consists of several hundred named genes, plus additional gene combinations and other heritable variants. There are about 1000 chromosomal aberrations (e.g., translocations and inversions) and stocks with abnormal chromosome numbers (e.g., tetraploids). Genetic data describing the maize mutant stocks as well as myriad other data about maize genetics can be accessed at MaizeGDB, the Maize Genetics and Genomics Database.

 

In 2005, the US National Science Foundation (NSF), Department of Agriculture (USDA) and the Department of Energy (DOE) formed a consortium to sequence the B73 maize genome. The resulting DNA sequence data was deposited immediately into GenBank, a public repository for genome-sequence data. Sequences and genome annotations have also been made available throughout the project's lifetime at the project's official site.

 

Primary sequencing of the maize genome was completed in 2008. On November 20, 2009, the consortium published results of its sequencing effort in Science. The genome, 85% of which is composed of transposons, was found to contain 32,540 genes (By comparison, the human genome contains about 2.9 billion bases and 26,000 genes). Much of the maize genome has been duplicated and reshuffled by helitrons—group of rolling circle transposons.

 

In Z. mays and various other angiosperms the MADS-box motif is involved in floral development. Early study in several angiosperm models including Z. mays was the beginning of research into the molecular evolution of floral structure in general, as well as their role in nonflowering plants.

 

EVOLUTION

As with many plants and animals, Z. mays has a positive correlation between effective population size and the magnitude of selection pressure. Z. m. having an EPS of ~650,000, it clusters with others of about the same EPS, and has 79% of its amino acid sites under selection.

 

Recombination is a significant source of diversity in Z. mays. (Note that this finding supersedes previous studies which showed no such correlation.)

 

This recombination/diversity effect is seen throughout plants but is also found to not occur – or not as strongly – in regions of high gene density. This is likely the reason that domesticated Z. mays has not seen as much of an increase in diversity within areas of higher density as in regions of lower density, although there is more evidence in other plants.

 

Some lines of maize have undergone ancient polyploidy events, starting 11m years ago. Over that time ~72% of polyploid duplicated genes have been retained, which is higher than other plants with older polyploidy events. Thus maize may be due to lose more duplicate genes as time goes along, similar to the course followed by the genomes of other plants. If so - if gene loss has merely not occurred yet - that could explain the lack of observed positive selection and lower negative selection which are observed in otherwise similar plants, i.e. also naturally outcrossing and with similar effective population sizes.

 

Ploidy does not appear to influence EPS or magnitude of selection effect in maize.

 

BREEDING

Maize reproduces sexually each year. This randomly selects half the genes from a given plant to propagate to the next generation, meaning that desirable traits found in the crop (like high yield or good nutrition) can be lost in subsequent generations unless certain techniques are used.

 

Maize breeding in prehistory resulted in large plants producing large ears. Modern breeding began with individuals who selected highly productive varieties in their fields and then sold seed to other farmers. James L. Reid was one of the earliest and most successful developing Reid's Yellow Dent in the 1860s. These early efforts were based on mass selection. Later breeding efforts included ear to row selection (C. G. Hopkins c. 1896), hybrids made from selected inbred lines (G. H. Shull, 1909), and the highly successful double cross hybrids using four inbred lines (D. F. Jones c. 1918, 1922). University supported breeding programs were especially important in developing and introducing modern hybrids. By the 1930s, companies such as Pioneer devoted to production of hybrid maize had begun to influence long-term development. Internationally important seed banks such as the International Maize and Wheat Improvement Center (CIMMYT) and the US bank at the Maize Genetics Cooperation Stock Center University of Illinois at Urbana-Champaign maintain germplasm important for future crop development.

 

Since the 1940s the best strains of maize have been first-generation hybrids made from inbred strains that have been optimized for specific traits, such as yield, nutrition, drought, pest and disease tolerance. Both conventional cross-breeding and genetic modification have succeeded in increasing output and reducing the need for cropland, pesticides, water and fertilizer. There is conflicting evidence to support the hypothesis that maize yield potential has increased over the past few decades. This suggests that changes in yield potential are associated with leaf angle, lodging resistance, tolerance of high plant density, disease/pest tolerance, and other agronomic traits rather than increase of yield potential per individual plant.

 

Tropical landraces remain an important and underutilized source of resistance alleles for for disease and for herbivores. Notable discoveries of rare alleles for this purpose were made by Dao et al 2014 and Sood et al 2014.

 

GLOBAL PROGRAM

CIMMYT operates a conventional breeding program to provide optimized strains. The program began in the 1980s. Hybrid seeds are distributed in Africa by the Drought Tolerant Maize for Africa project.

 

GENETIC MODIFICATION

Genetically modified (GM) maize was one of the 26 GM crops grown commercially in 2016. The vast majority of this is Bt maize. Grown since 1997 in the United States and Canada, 92% of the US maize crop was genetically modified in 2016 and 33% of the worldwide maize crop was GM in 2016. As of 2011, Herbicide-tolerant maize varieties were grown in Argentina, Australia, Brazil, Canada, China, Colombia, El Salvador, the European Union, Honduras, Japan, Korea, Malaysia, Mexico, New Zealand, Philippines, the Russian Federation, Singapore, South Africa, Taiwan, Thailand, and the United States. Insect-resistant maize was grown in Argentina, Australia, Brazil, Canada, Chile, China, Colombia, Egypt, the European Union, Honduras, Japan, Korea, Malaysia, Mexico, New Zealand, Philippines, South Africa, Switzerland, Taiwan, the United States, and Uruguay.

 

In September 2000, up to $50 million worth of food products were recalled due to the presence of Starlink genetically modified corn, which had been approved only for animal consumption and had not been approved for human consumption, and was subsequently withdrawn from the market.

 

ORIGIN

Maize is the domesticated variant of teosinte. The two plants have dissimilar appearance, maize having a single tall stalk with multiple leaves and teosinte being a short, bushy plant. The difference between the two is largely controlled by differences in just two genes, called grassy tillers-1 (gt1, A0A317YEZ1) and teosinte branched-1 (tb1, Q93WI2).

 

Several theories had been proposed about the specific origin of maize in Mesoamerica:

 

It is a direct domestication of a Mexican annual teosinte, Zea mays ssp. parviglumis, native to the Balsas River valley in south-eastern Mexico, with up to 12% of its genetic material obtained from Zea mays ssp. mexicana through introgression.

It has been derived from hybridization between a small domesticated maize (a slightly changed form of a wild maize) and a teosinte of section Luxuriantes, either Z. luxurians or Z. diploperennis.

It has undergone two or more domestications either of a wild maize or of a teosinte. (The term "teosinte" describes all species and subspecies in the genus Zea, excluding Zea mays ssp. mays.)

It has evolved from a hybridization of Z. diploperennis by Tripsacum dactyloides.

 

In the late 1930s, Paul Mangelsdorf suggested that domesticated maize was the result of a hybridization event between an unknown wild maize and a species of Tripsacum, a related genus. This theory about the origin of maize has been refuted by modern genetic testing, which refutes Mangelsdorf's model and the fourth listed above. 

 

The teosinte origin theory was proposed by the Russian botanist Nikolai Ivanovich Vavilov in 1931 and the later American Nobel Prize-winner George Beadle in 1932.: 10  It is supported experimentally and by recent studies of the plants' genomes. Teosinte and maize can cross-breed and produce fertile offspring. A number of questions remain concerning the species, among them:

 

how the immense diversity of the species of sect. Zea originated,

how the tiny archaeological specimens of 3500–2700 BC could have been selected from a teosinte, and

how domestication could have proceeded without leaving remains of teosinte or maize with teosintoid traits earlier than the earliest known until recently, dating from ca. 1100 BC.

 

The domestication of maize is of particular interest to researchers—archaeologists, geneticists, ethnobotanists, geographers, etc. The process is thought by some to have started 7,500 to 12,000 years ago. Research from the 1950s to 1970s originally focused on the hypothesis that maize domestication occurred in the highlands between the states of Oaxaca and Jalisco, because the oldest archaeological remains of maize known at the time were found there.

Connection with 'parviglumis' subspecies

Genetic studies, published in 2004 by John Doebley, identified Zea mays ssp. parviglumis, native to the Balsas River valley in Mexico's southwestern highlands, and also known as Balsas teosinte, as being the crop wild relative that is genetically most similar to modern maize. This was confirmed by further studies, which refined this hypothesis somewhat. Archaeobotanical studies, published in 2009, point to the middle part of the Balsas River valley as the likely location of early domestication; this river is not very long, so these locations are not very distant. Stone milling tools with maize residue have been found in an 8,700 year old layer of deposits in a cave not far from Iguala, Guerrero.

 

Doebley was part of the team that first published, in 2002, that maize had been domesticated only once, about 9,000 years ago, and then spread throughout the Americas.

 

A primitive corn was being grown in southern Mexico, Central America, and northern South America 7,000 years ago. Archaeological remains of early maize ears, found at Guila Naquitz Cave in the Oaxaca Valley, date back roughly 6,250 years; the oldest ears from caves near Tehuacan, Puebla, 5,450 B.P.

 

Maize pollen dated to 7,300 B.P. from San Andres, Tabasco, on the Caribbean coast has also been recovered.

 

As maize was introduced to new cultures, new uses were developed and new varieties selected to better serve in those preparations. Maize was the staple food, or a major staple – along with squash, Andean region potato, quinoa, beans, and amaranth – of most pre-Columbian North American, Mesoamerican, South American, and Caribbean cultures. The Mesoamerican civilization, in particular, was deeply interrelated with maize. Its traditions and rituals involved all aspects of maize cultivation – from the planting to the food preparation. Maize formed the Mesoamerican people's identity.

 

It is unknown what precipitated its domestication, because the edible portion of the wild variety is too small, and hard to obtain, to be eaten directly, as each kernel is enclosed in a very hard bivalve shell.

 

In 1939, George Beadle demonstrated that the kernels of teosinte are readily "popped" for human consumption, like modern popcorn.[91] Some have argued it would have taken too many generations of selective breeding to produce large, compressed ears for efficient cultivation. However, studies of the hybrids readily made by intercrossing teosinte and modern maize suggest this objection is not well founded.

 

SPREADING TO THE NORTH

Around 4,500 ago, maize began to spread to the north; it was first cultivated in what is now the United States at several sites in New Mexico and Arizona, about 4,100 ago.

 

During the first millennium AD, maize cultivation spread more widely in the areas north. In particular, the large-scale adoption of maize agriculture and consumption in eastern North America took place about A.D. 900. Native Americans cleared large forest and grassland areas for the new crop.

 

In 2005, research by the USDA Forest Service suggested that the rise in maize cultivation 500 to 1,000 years ago in what is now the southeastern United States corresponded with a decline of freshwater mussels, which are very sensitive to environmental changes.

 

CULTIVATION

PLANTING

Because it is cold-intolerant, in the temperate zones maize must be planted in the spring. Its root system is generally shallow, so the plant is dependent on soil moisture. As a plant that uses C4 carbon fixation, maize is a considerably more water-efficient crop than plants that use C3 carbon fixation such as alfalfa and soybeans. Maize is most sensitive to drought at the time of silk emergence, when the flowers are ready for pollination. In the United States, a good harvest was traditionally predicted if the maize was "knee-high by the Fourth of July", although modern hybrids generally exceed this growth rate. Maize used for silage is harvested while the plant is green and the fruit immature. Sweet corn is harvested in the "milk stage", after pollination but before starch has formed, between late summer and early to mid-autumn. Field maize is left in the field until very late in the autumn to thoroughly dry the grain, and may, in fact, sometimes not be harvested until winter or even early spring. The importance of sufficient soil moisture is shown in many parts of Africa, where periodic drought regularly causes maize crop failure and consequent famine. Although it is grown mainly in wet, hot climates, it has been said to thrive in cold, hot, dry or wet conditions, meaning that it is an extremely versatile crop.

 

Maize was planted by the Native Americans in hills, in a complex system known to some as the Three Sisters. Maize provided support for beans, and the beans provided nitrogen derived from nitrogen-fixing rhizobia bacteria which live on the roots of beans and other legumes; and squashes provided ground cover to stop weeds and inhibit evaporation by providing shade over the soil. This method was replaced by single species hill planting where each hill 60–120 cm (2 ft 0 in–3 ft 11 in) apart was planted with three or four seeds, a method still used by home gardeners. A later technique was "checked maize", where hills were placed

 

1 m (40 in) apart in each direction, allowing cultivators to run through the field in two directions. In more arid lands, this was altered and seeds were planted in the bottom of 10–12 cm (4–4+1⁄2 in) deep furrows to collect water. Modern technique plants maize in rows which allows for cultivation while the plant is young, although the hill technique is still used in the maize fields of some Native American reservations. When maize is planted in rows, it also allows for planting of other crops between these rows to make more efficient use of land space.

 

In most regions today, maize grown in residential gardens is still often planted manually with a hoe, whereas maize grown commercially is no longer planted manually but rather is planted with a planter. In North America, fields are often planted in a two-crop rotation with a nitrogen-fixing crop, often alfalfa in cooler climates and soybeans in regions with longer summers. Sometimes a third crop, winter wheat, is added to the rotation.

 

Many of the maize varieties grown in the United States and Canada are hybrids. Often the varieties have been genetically modified to tolerate glyphosate or to provide protection against natural pests. Glyphosate is an herbicide which kills all plants except those with genetic tolerance. This genetic tolerance is very rarely found in nature.

 

In the midwestern United States, low-till or no-till farming techniques are usually used. In low-till, fields are covered once, maybe twice, with a tillage implement either ahead of crop planting or after the previous harvest. The fields are planted and fertilized. Weeds are controlled through the use of herbicides, and no cultivation tillage is done during the growing season. This technique reduces moisture evaporation from the soil, and thus provides more moisture for the crop. The technologies mentioned in the previous paragraph enable low-till and no-till farming. Weeds compete with the crop for moisture and nutrients, making them undesirable.

 

HARVESTING

Before the 20th century, all maize harvesting was by manual labour, by grazing, or by some combination of those. Whether the ears were hand-picked and the stover was grazed, or the whole plant was cut, gathered, and shocked, people and livestock did all the work. Between the 1890s and the 1970s, the technology of maize harvesting expanded greatly. Today, all such technologies, from entirely manual harvesting to entirely mechanized, are still in use to some degree, as appropriate to each farm's needs, although the thoroughly mechanized versions predominate, as they offer the lowest unit costs when scaled to large farm operations. For small farms, their unit cost can be too high, as their higher fixed cost cannot be amortized over as many units.[citation needed]

 

Before World War II, most maize in North America was harvested by hand. This involved a large number of workers and associated social events (husking or shucking bees). From the 1890s onward, some machinery became available to partially mechanize the processes, such as one- and two-row mechanical pickers (picking the ear, leaving the stover) and corn binders, which are reaper-binders designed specifically for maize (for example, Video on YouTube). The latter produce sheaves that can be shocked. By hand or mechanical picker, the entire ear is harvested, which then requires a separate operation of a maize sheller to remove the kernels from the ear. Whole ears of maize were often stored in corn cribs, and these whole ears are a sufficient form for some livestock feeding use. Today corn cribs with whole ears, and corn binders, are less common because most modern farms harvest the grain from the field with a combine and store it in bins. The combine with a corn head (with points and snap rolls instead of a reel) does not cut the stalk; it simply pulls the stalk down. The stalk continues downward and is crumpled into a mangled pile on the ground, where it usually is left to become organic matter for the soil. The ear of maize is too large to pass between slots in a plate as the snap rolls pull the stalk away, leaving only the ear and husk to enter the machinery. The combine separates the husk and the cob, keeping only the kernels.

When maize is a silage crop, the entire plant is usually chopped at once with a forage harvester (chopper) and ensiled in silos or polymer wrappers. Ensiling of sheaves cut by a corn binder was formerly common in some regions but has become uncommon. For storing grain in bins, the moisture of the grain must be sufficiently low to avoid spoiling. If the moisture content of the harvested grain is too high, grain dryers are used to reduce the moisture content by blowing heated air through the grain. This can require large amounts of energy in the form of combustible gases (propane or natural gas) and electricity to power the blowers.

 

PRODUCTION

Maize is widely cultivated throughout the world, and a greater weight of maize is produced each year than any other grain. In 2018, total world production was 1.15 billion tonnes, led by the United States with 34.2% of the total (table). China produced 22.4% of the global total.

 

UNITED STATES

In 2016, maize production was forecast to be over 380 million metric tons (15 billion bushels), an increase of 11% over 2014 American production. Based on conditions as of August 2016, the expected yield would be the highest ever for the United States. The area of harvested maize was forecast to be 35 million hectares (87 million acres), an increase of 7% over 2015. Maize is especially popular in Midwestern states such as Indiana, Iowa, and Illinois; in the latter, it was named the state's official grain in 2017.

 

STORAGE

Drying is vital to prevent or at least reduce mycotoxin contamination. Aspergillus and Fusarium spp. are the most common mycotoxin sources, but there are others. Altogether maize contaminants are so common, and this crop is so economically important, that maize mycotoxins are among the most important in agriculture in general.

 

USES

HUMAN FOOD

Maize and cornmeal (ground dried maize) constitute a staple food in many regions of the world. Maize is used to produce cornstarch, a common ingredient in home cooking and many industrialized food products. Maize starch can be hydrolyzed and enzymatically treated to produce syrups, particularly high fructose corn syrup, a sweetener; and also fermented and distilled to produce grain alcohol. Grain alcohol from maize is traditionally the source of Bourbon whiskey. Corn flour is used to make cornbread and other baked products.

 

In prehistoric times Mesoamerican women used a metate to process maize into ground cornmeal, allowing the preparation of foods that were more calorie dense than popcorn. After ceramic vessels were invented the Olmec people began to cook maize together with beans, improving the nutritional value of the staple meal. Although maize naturally contains niacin, an important nutrient, it was not bioavailable without the process of nixtamalization. The Maya used nixtamal meal to make varieties of porridges and tamales. The process was later used in the cuisine of the American South to prepare corn for grits and hominy.

 

Maize is a staple of Mexican cuisine. Masa (cornmeal treated with limewater) is the main ingredient for tortillas, atole and many other dishes of Central American food. It is the main ingredient of corn tortilla, tamales, pozole, atole and all the dishes based on them, like tacos, quesadillas, chilaquiles, enchiladas, tostadas and many more. In Mexico the fungus of maize, known as huitlacoche, is considered a delicacy.

 

Coarse maize meal is made into a thick porridge in many cultures: from the polenta of Italy, the angu of Brazil, the mămăligă of Romania, to cornmeal mush in the US (or hominy grits in the South) or the food called mieliepap in South Africa and sadza, nshima, ugali and other names in other parts of Africa. Introduced into Africa by the Portuguese in the 16th century, maize has become Africa's most important staple food crop. These are commonly eaten in the Southeastern United States, foods handed down from Native Americans, who called the dish sagamite.

 

Maize can also be harvested and consumed in the unripe state, when the kernels are fully grown but still soft. Unripe maize must usually be cooked to become palatable; this may be done by simply boiling or roasting the whole ears and eating the kernels right off the cob. Sweet corn, a genetic variety that is high in sugars and low in starch, is usually consumed in the unripe state. Such corn on the cob is a common dish in the United States, Canada, United Kingdom, Cyprus, some parts of South America, and the Balkans, but virtually unheard of in some European countries. Corn on the cob was hawked on the streets of early 19th-century New York City by poor, barefoot "Hot Corn Girls", who were thus the precursors of hot dog carts, churro wagons, and fruit stands seen on the streets of big cities today.

 

Within the United States, the usage of maize for human consumption constitutes only around 1/40th of the amount grown in the country. In the United States and Canada, maize is mostly grown to feed livestock, as forage, silage (made by fermentation of chopped green cornstalks), or grain. Maize meal is also a significant ingredient of some commercial animal food products.

 

NUTRITIONAL VALUE

Raw, yellow, sweet maize kernels are composed of 76% water, 19% carbohydrates, 3% protein, and 1% fat (table). In a 100-gram serving, maize kernels provide 86 calories and are a good source (10–19% of the Daily Value) of the B vitamins, thiamin, niacin (but see Pellagra warning below), pantothenic acid (B5) and folate (right table for raw, uncooked kernels, USDA Nutrient Database). In moderate amounts, they also supply dietary fiber and the essential minerals, magnesium and phosphorus whereas other nutrients are in low amounts (table).

 

Maize has suboptimal amounts of the essential amino acids tryptophan and lysine, which accounts for its lower status as a protein source. However, the proteins of beans and legumes complement those of maize.

 

FEED AND FODDER FOR LIVESTOCK

Maize is a major source of both grain feed and fodder for livestock. It is fed to the livestock in various ways. When it is used as a grain crop, the dried kernels are used as feed. They are often kept on the cob for storage in a corn crib, or they may be shelled off for storage in a grain bin. The farm that consumes the feed may produce it, purchase it on the market, or some of both. When the grain is used for feed, the rest of the plant (the corn stover) can be used later as fodder, bedding (litter), or soil amendment. When the whole maize plant (grain plus stalks and leaves) is used for fodder, it is usually chopped all at once and ensilaged, as digestibility and palatability are higher in the ensilaged form than in the dried form. Maize silage is one of the most valuable forages for ruminants. Before the advent of widespread ensilaging, it was traditional to gather the corn into shocks after harvesting, where it dried further. With or without a subsequent move to the cover of a barn, it was then stored for weeks to several months until fed to the livestock. Today ensilaging can occur not only in siloes but also in silage wrappers. However, in the tropics, maize can be harvested year-round and fed as green forage to the animals.

 

CHEMICALS

Starch from maize can also be made into plastics, fabrics, adhesives, and many other chemical products.

 

The corn steep liquor, a plentiful watery byproduct of maize wet milling process, is widely used in the biochemical industry and research as a culture medium to grow many kinds of microorganisms.

 

Chrysanthemin is found in purple corn and is used as a food coloring.

 

BIO-FUEL

"Feed maize" is being used increasingly for heating; specialized corn stoves (similar to wood stoves) are available and use either feed maize or wood pellets to generate heat. Maize cobs are also used as a biomass fuel source. Maize is relatively cheap and home-heating furnaces have been developed which use maize kernels as a fuel. They feature a large hopper that feeds the uniformly sized maize kernels (or wood pellets or cherry pits) into the fire.[citation needed]

 

Maize is increasingly used as a feedstock for the production of ethanol fuel.[120] When considering where to construct an ethanol plant, one of the site selection criteria is to ensure there is locally available feedstock. Ethanol is mixed with gasoline to decrease the amount of pollutants emitted when used to fuel motor vehicles. High fuel prices in mid-2007 led to higher demand for ethanol, which in turn led to higher prices paid to farmers for maize. This led to the 2007 harvest being one of the most profitable maize crops in modern history for farmers. Because of the relationship between fuel and maize, prices paid for the crop now tend to track the price of oil.

 

The price of food is affected to a certain degree by the use of maize for biofuel production. The cost of transportation, production, and marketing are a large portion (80%) of the price of food in the United States. Higher energy costs affect these costs, especially transportation. The increase in food prices the consumer has been seeing is mainly due to the higher energy cost. The effect of biofuel production on other food crop prices is indirect. Use of maize for biofuel production increases the demand, and therefore price of maize. This, in turn, results in farm acreage being diverted from other food crops to maize production. This reduces the supply of the other food crops and increases their prices.

 

Maize is widely used in Germany as a feedstock for biogas plants. Here the maize is harvested, shredded then placed in silage clamps from which it is fed into the biogas plants. This process makes use of the whole plant rather than simply using the kernels as in the production of fuel ethanol.

 

A biomass gasification power plant in Strem near Güssing, Burgenland, Austria, began in 2005. Research is being done to make diesel out of the biogas by the Fischer Tropsch method.

 

Increasingly, ethanol is being used at low concentrations (10% or less) as an additive in gasoline (gasohol) for motor fuels to increase the octane rating, lower pollutants, and reduce petroleum use (what is nowadays also known as "biofuels" and has been generating an intense debate regarding the human beings' necessity of new sources of energy, on the one hand, and the need to maintain, in regions such as Latin America, the food habits and culture which has been the essence of civilizations such as the one originated in Mesoamerica; the entry, January 2008, of maize among the commercial agreements of NAFTA has increased this debate, considering the bad labor conditions of workers in the fields, and mainly the fact that NAFTA "opened the doors to the import of maize from the United States, where the farmers who grow it receive multimillion-dollar subsidies and other government supports. ... According to OXFAM UK, after NAFTA went into effect, the price of maize in Mexico fell 70% between 1994 and 2001. The number of farm jobs dropped as well: from 8.1 million in 1993 to 6.8 million in 2002. Many of those who found themselves without work were small-scale maize growers."). However, introduction in the northern latitudes of the US of tropical maize for biofuels, and not for human or animal consumption, may potentially alleviate this.

 

COMMODITY

Maize is bought and sold by investors and price speculators as a tradable commodity using corn futures contracts. These "futures" are traded on the Chicago Board of Trade (CBOT) under ticker symbol C. They are delivered every year in March, May, July, September, and December.

Ornamental and other uses

 

Some forms of the plant are occasionally grown for ornamental use in the garden. For this purpose, variegated and colored leaf forms as well as those with colorful ears are used.

 

Corncobs can be hollowed out and treated to make inexpensive smoking pipes, first manufactured in the United States in 1869.

 

An unusual use for maize is to create a "corn maze" (or "maize maze") as a tourist attraction. The idea of a maize maze was introduced by the American Maze Company who created a maze in Pennsylvania in 1993. Traditional mazes are most commonly grown using yew hedges, but these take several years to mature. The rapid growth of a field of maize allows a maze to be laid out using GPS at the start of a growing season and for the maize to grow tall enough to obstruct a visitor's line of sight by the start of the summer. In Canada and the US, these are popular in many farming communities.

 

Maize kernels can be used in place of sand in a sandboxlike enclosure for children's play.

 

Stigmas from female maize flowers, popularly called corn silk, are sold as herbal supplements.

 

Maize is used as a fish bait, called "dough balls". It is particularly popular in Europe for coarse fishing.

 

Additionally, feed corn is sometimes used by hunters to bait animals such as deer or wild hogs.

 

UNITED STATES USAGE BREAKDOWN

The breakdown of usage of the 12.1-billion-bushel (307-million-tonne) 2008 US maize crop was as follows, according to the World Agricultural Supply and Demand Estimates Report by the USDA.In the US since 2009/2010, maize feedstock use for ethanol production has somewhat exceeded direct use for livestock feed; maize use for fuel ethanol was 5,130 million bushels (130 million tonnes) in the 2013/2014 marketing year.A fraction of the maize feedstock dry matter used for ethanol production is usefully recovered as DDGS (dried distillers grains with solubles). In the 2010/2011 marketing year, about 29.1 million tonnes of DDGS were fed to US livestock and poultry. Because starch utilization in fermentation for ethanol production leaves other grain constituents more concentrated in the residue, the feed value per kg of DDGS, with regard to ruminant-metabolizable energy and protein, exceeds that of the grain. Feed value for monogastric animals, such as swine and poultry, is somewhat lower than for ruminants.

 

HAZARDS

PELLAGRA

When maize was first introduced into farming systems other than those used by traditional native-American peoples, it was generally welcomed with enthusiasm for its productivity. However, a widespread problem of malnutrition soon arose wherever maize was introduced as a staple food. This was a mystery, since these types of malnutrition were not normally seen among the indigenous Americans, for whom maize was the principal staple food.

 

It was eventually discovered that the indigenous Americans had learned to soak maize in alkali — water (the process now known as nixtamalization) — made with ashes and lime (calcium oxide) since at least 1200–1500 BC by Mesoamericans. They did this to liberate the corn hulls, but (unbeknownst to natives or colonists) it coincidentally liberates the B-vitamin niacin, the lack of which was the underlying cause of the condition known as pellagra.

 

Maize was introduced into the diet of non-indigenous Americans without the necessary cultural knowledge acquired over thousands of years in the Americas. In the late 19th century, pellagra reached epidemic proportions in parts of the southern US, as medical researchers debated two theories for its origin: the deficiency theory (which was eventually shown to be true) said that pellagra was due to a deficiency of some nutrient, and the germ theory said that pellagra was caused by a germ transmitted by stable flies. A third theory, promoted by the eugenicist Charles Davenport, held that people only contracted pellagra if they were susceptible to it due to certain "constitutional, inheritable" traits of the affected individual.

 

Once alkali processing and dietary variety were understood and applied, pellagra disappeared in the developed world. The development of high lysine maize and the promotion of a more balanced diet have also contributed to its demise. Pellagra still exists today in food-poor areas and refugee camps where people survive on donated maize.

 

ALLERGY

Maize contains lipid transfer protein, an indigestible protein that survives cooking. This protein has been linked to a rare and understudied allergy to maize in humans. The allergic reaction can cause skin rash, swelling or itching of mucous membranes, diarrhea, vomiting, asthma and, in severe cases, anaphylaxis. It is unclear how common this allergy is in the general population.

 

MYCOTOXINS

Fungicide application does not reduce fungal growth or mycotoxin dramatically, although it can be a part of a successful reduction strategy. Among the most common toxins are those produced by Aspergillus and Fusarium spp. The most common toxins are aflatoxins, fumonisins, zearalenone, and ochratoxin A. Bt maize discourages insect vectors and by so doing it dramatically reduces concentrations of fumonisins, significantly reduces aflatoxins, but only mildly reduces others.

 

ART

Maize has been an essential crop in the Andes since the pre-Columbian era. The Moche culture from Northern Peru made ceramics from earth, water, and fire. This pottery was a sacred substance, formed in significant shapes and used to represent important themes. Maize was represented anthropomorphically as well as naturally.

 

In the United States, maize ears along with tobacco leaves are carved into the capitals of columns in the United States Capitol building. Maize itself is sometimes used for temporary architectural detailing when the intent is to celebrate the fall season, local agricultural productivity and culture. Bundles of dried maize stalks are often displayed along with pumpkins, gourds and straw in autumnal displays outside homes and businesses. A well-known example of architectural use is the Corn Palace in Mitchell, South Dakota, which uses cobs and ears of colored maize to implement a mural design that is recycled annually. Another well-known example is the Field of Corn sculpture in Dublin, Ohio, where hundreds of concrete ears of corn stand in a grassy field.

 

A maize stalk with two ripe ears is depicted on the reverse of the Croatian 1 lipa coin, minted since 1993.

 

WIKIPEDIA

Less developed one on left has squatter profile.

Whorls convex without angulation, except sub-sutural sloping bevel (1).

Costae absent from bevel (2).

Bevel conspicuous on thin translucent specimen (3) as it is thicker.

Weak labial varix (4) set well back from thin palatal lip.

Bevel broader where unites with labial varix (5).

Periphery of body-whorl without angulation on juveniles (6 & 7).

H. 1.3 mm, 1.6 mm and 1.6 mm, Brighton, England, November 1997.

Leg. coll. J.M. Light.

 

Full SPECIES DESCRIPTION BELOW

Sets of OTHER SPECIES: www.flickr.com/photos/56388191@N08/collections/

 

Pusillina inconspicua (Alder, 1844)

 

Full SPECIES DESCRIPTION BELOW

Sets of OTHER SPECIES: www.flickr.com/photos/56388191@N08/collections/

 

Synonyms: Rissoa inconspicua Alder, 1844 [in Forbes & Hanley and in Jeffreys]; Turboella densa Nordsieck, 1972; Turboella diversa Nordsieck, 1972;

Current taxonomy: World Register of Marine Species (WoRMS) www.marinespecies.org/aphia.php?p=taxdetails&id=141334

Meaning of name: Pusillina = (Latin) very small.

inconspicua = (Latin) inconspicuous.

 

Vernacular: tyndskallet tangsnegl (Danish); dwerg-drijfhoren (Dutch); mindre bandtångsnäcka (Swedish);

 

GLOSSARY below.

 

Preface

“ a confusing 'species' and it is not easy to be convinced that not a species complex is involved here. - - - samples [from all along Norwegian coast] document a high degree of local and geographical variability.” (Høisaeter, 2009.)

 

“Rissoa inconspicua is perhaps one of the most variable of the genus, - - Alder's original delineation of it combines characters that are not often found together in such high development; hence, despite its correctness, few specimens would be positively determined by comparison with it.” (Forbes & Hanley, 1853.)

 

Shell description

P. inconspicua is a polymorphic species, varying greatly from site to site and within a single site both on a single date and seasonally 00Pi flic.kr/p/2pN2Cyc . More than one species may be involved. The maximum height of adults varies locally from 1.3 mm to 3 mm. The profile of adults varies from squat dwarf (spire 23%, body whorl 77% of shell-height) to fairly tall (spire 40%, body whorl 60% of shell-height) 01Pi flic.kr/p/wNFGTS . Juveniles usually have lower profile than adults 02Pi flic.kr/p/wwNmaW . The shells are thin and very fragile. The whorls are clearly defined by the suture, and distinctly convex without angulation except for narrow sloping bevel below the suture 02Pi flic.kr/p/wwNmaW . The bevel is conspicuous on thin translucent specimens as it is thicker than the rest of the shell. Sometimes the bevel is broader where it acts as extension of a labial varix. The periphery of the body whorl is well rounded on adults and juveniles. The sculpture varies; Alder (1844) stated, “upper whorls smooth; the penultimate [adapical] half of the last whorls generally marked with numerous very delicate and faint ribs or plicae [costae], about thirty in number, the bases of which are crossed on the body whorl by a few faint spiral striae, giving that part a reticulated appearance. The whole of the markings are very delicate and sometimes entirely wanting.” Only a small minority distinctly display all features illustrated 03Pi flic.kr/p/wNFGy3 and described by Alder. For example there was only one costate specimen among 359 from three Norwegian sites (Høisaeter, 2009). Graham (1988) stated “nearly always numerous fine costae”, but a very small minority of hundreds of shells examined by IFS had them. A great number of merging forms result from kaleidoscopic combinations of Alder's shell-features, but a single form often predominates at individual sites. But Warén (1996) considered it “unusually constant in its shell morphology, from northern Norway to the Mediterranean”. Sculpture variations include distinct, fine, numerous costae (9-15 on apertural view of body whorl) 04Pi flic.kr/p/wwNkpY ; no costae 05Pi flic.kr/p/wM6kuY ; square-reticulation created by spiral striae crossing distinct costae 06Pi flic.kr/p/wwNhrA ; and weak reticulation created by spiral striae crossing barely visible costae 07Pi flic.kr/p/wPVxPz . Costae, when present, do not cross the sub-sutural bevel or basal half of the body whorl 02Pi flic.kr/p/wwNmaW , 04Pi flic.kr/p/wwNkpY & 06Pi flic.kr/p/wwNhrA .

The embryonic and larval protoconch forms the three apical whorls. It always lacks costae, is usually the same ground colour as the rest of the shell and has a tiny purple, occasionally yellow, apical spot confined to the single embryonic whorl, not extending onto the two larval whorls of the protoconch. The apical spot may be distinct 08Pi flic.kr/p/vSoFej , faint, very minute 09Pi flic.kr/p/wwNiwu or absent 10Pi flic.kr/p/wwVxU4 . On shells bearing brown markings the white protoconch contrasts distinctly with the rest of the shell 11Pi flic.kr/p/wwVxZe & 12Pi flic.kr/p/wPpVUa .

The ground colour of the shell is whitish, sometimes with patches of light horn-colour 04Pi flic.kr/p/wwNkpY ; more 08Pi flic.kr/p/vSoFej or less 05Pi flic.kr/p/wM6kuY translucent; with axial streaks of brown varying from strongly 11Pi flic.kr/p/wwVxZe to very weakly 05Pi flic.kr/p/wM6kuY developed or, very often, missing 13Pi flic.kr/p/wPVw1e . Some live specimens have a layer which comes off if a shell is rotted out in water; compare 09Pi flic.kr/p/wwNiwu with 10Pi flic.kr/p/wwVxU4 . Many mature adults have a broad white labial varix set back from outer lip of the aperture. Usually it is not very thick and is most discernible on shells which are brown-streaked 11Pi flic.kr/p/wwVxZe or thin and almost transparent 08Pi flic.kr/p/vSoFej . The varix is missing from juveniles and from adults at some sites 10Pi flic.kr/p/wwVxU4 & 13Pi flic.kr/p/wPVw1e . The aperture height is 35% to 50% of shell height. The shape varies but many are “ straight at the pillar, [columellar lip] and slightly angulated at the base beneath it” Alder (1844) 01Pi flic.kr/p/wNFGTS & 03Pi flic.kr/p/wNFGy3 . The parietal lip is a thin glaze on the body whorl and the peristome is not distinctly continuous there 01Pi flic.kr/p/wNFGTS . The aperture rim is usually white and occasionally has slight brown marks. The curved outer (palatal) lip, has a thin edge even on mature specimens with a labial varix 06Pi flic.kr/p/wwNhrA as the varix is rarely thick and usually set back from the edge. The columellar lip is slightly reflected, usually leaving an umbilical groove between it and body whorl 01Pi flic.kr/p/wNFGTS & 03Pi flic.kr/p/wNFGy3 . Internally, the aperture is translucent white showing any brown exterior marks 01Pi flic.kr/p/wNFGTS .

 

Body description

Caveat: most live images in this account are from single site in North Wales. It is possible that soft-parts at other sites may vary. For example, Høisaeter (2009) found the dark head pattern at one site to be much faded at two other sites.

The flesh is translucent whitish with some opaque blotches of yellow or white. The snout is deeply bifid 14Pi flic.kr/p/wPpV8R and often has a broad medial blackish or brown-umber band which extends onto the head and body 14Pi flic.kr/p/wPpV8R . The band was found on all live specimens examined/photographed from the main Welsh site. It was more faded on a specimen from another site, but this may be because it was a juvenile 15Pi flic.kr/p/2pNkwwx . Often, there are a few opaque white or yellow marks on the snout 16Pi flic.kr/p/wPpUYn . When the pale-yellow salivary glands and buccal mass are retracted, the snout is translucent whitish and the head is yellow 16Pi flic.kr/p/wPpUYn . When glands and buccal mass are pushed forwards, the snout is yellow and the head is translucent whitish 17Pi flic.kr/p/vSoCDu .

The cephalic tentacles are translucent white with two parallel irregular rows of substantial, opaque-white, hyphen-like marks in each tentacle 18Pi flic.kr/p/wNFBVf ; in lateral view one row may conceal the other 10Pi flic.kr/p/wwVxU4 . A slight swelling at the base of the tentacle 19Pi flic.kr/p/wwNcPj bears a large black eye with a dorsally-enclosing, semi-circular, opaque-yellow mark 10Pi flic.kr/p/wwVxU4 . The dorsal surface of the foot is translucent whitish with a broad, dark, transverse band anterior of the mid-point 16Pi flic.kr/p/wPpUYn . There are two dark-purple or black longitudinal lines on each side; one dorso-lateral and one on the periphery of the foot (Alder, 1844) 03Pi flic.kr/p/wNFGy3 ; they are often faint and partial 20Pi flic.kr/p/wM6ghj & 16Pi flic.kr/p/wPpUYn or imperceptible at some sites. The peripheral line often extends forwards well beyond the transverse band on the dorsal surface 21Pi flic.kr/p/wPVuEt . The anterior quarter of the foot has a whitish, heart-shaped, anterior pedal mucous gland 22Pi flic.kr/p/wM6g43 ; sometimes with blackish/grey surface blotch 23Pi flic.kr/p/wwNdfj & 16Pi flic.kr/p/wPpUYn . The posterior half of the foot has an opaque-white posterior pedal gland visible laterally 16Pi flic.kr/p/wPpUYn . The constriction in the foot shows as a lateral crease when the foot is contracted 10Pi flic.kr/p/wwVxU4 ; it facilitates transverse folding of the narrow foot 16Pi flic.kr/p/wPpUYn . When extended, the anterior of the sole is expanded; its bilaminate edge has within it the outlet of the heart-shaped anterior pedal mucous-gland 21Pi flic.kr/p/wPVuEt . Most of the posterior two-thirds of the sole is occupied by the opaque-white posterior pedal mucous-gland with a central pore 21Pi flic.kr/p/wPVuEt . The operculum is translucent horn-coloured. The opercular lobe is blackish or brownish at the anterior only 10Pi flic.kr/p/wwVxU4 The projecting posterior of the lobe is whitish 20Pi flic.kr/p/wM6ghj & 16Pi flic.kr/p/wPpUYn and sometimes difficult to discern against the similarly coloured foot 21Pi flic.kr/p/wPVuEt . A very long, translucent-white, finger-like metapodial tentacle is usually held clear of the foot-surface and extends from the opercular disc to well beyond the posterior of the foot 24Pi flic.kr/p/wwNd4h .

The mantle is greyish-white or yellowish-white 21Pi flic.kr/p/wPVuEt with a long, translucent pallial tentacle protruding beyond the shell 19Pi flic.kr/p/wwNcPj & 21Pi flic.kr/p/wPVuEt from adapical angle of shell-aperture 10Pi flic.kr/p/wwVxU4 .

A dissected ctenidium had short stout whitish filaments 25Pi flic.kr/p/wM6fa9 ; live specimens show it through the translucent shell as a row of yellow 26Pi flic.kr/p/wM6f1m or whitish 18Pi flic.kr/p/wNFBVf marks. The whitish penis with a blunt rounded tip and no filament is attached behind the right tentacle on males. It is very long and may extend back into the mantle cavity or protrude from the shell 27Pi flic.kr/p/wM6ePE .

  

Key identification features

The shell feature key in Waren (1996) states that identification of Rissoa and Pusillina shells should not be attempted without access to rich material, especially at brackish sites where variation, corrosion and encrustation are frequent (Waren, 1996).

Pusillina inconspicua

1) Tiny purple apical spot confined to single embryonic whorl on the protoconch 08Pi flic.kr/p/vSoFej ; diagnostic when present, but absent from some.

2) Two parallel rows of opaque white, hyphen-like marks in each translucent white cephalic tentacle 18Pi flic.kr/p/wNFBVf ; in lateral view one row may conceal other 10Pi flic.kr/p/wwVxU4 .

3) If present, 9-15 closely-spaced, fine costae (axial ribs) on apertural view of body whorl 30Pi flic.kr/p/vSxcVH . Many populations have few or no costate individuals.

4) Maximum height 3 mm, usually less. When shells with equal numbers of whorls are compared, P. inconspicua is shorter than R. parva and P. sarsii 29Pi flic.kr/p/wM6eG5 .

5) Long, whitish penis has a blunt rounded tip and no filament 27Pi flic.kr/p/wM6ePE .

6) On equal-sized specimens, the foot is wider than on R. parva 30Pi flic.kr/p/wwNbDo .

7) Opaque white posterior pedal gland stops well-short of edge of sole.

8) Snout often has broad medial blackish or brown-umber band

19Pi flic.kr/p/wwNcPj which extends onto head and body 14Pi flic.kr/p/wPpV8R .

9) Columellar lip slightly reflected, usually leaving an umbilical groove between it and body whorl 01Pi flic.kr/p/wNFGTS & 03Pi flic.kr/p/wNFGy3 .

10) Periphery of body whorl well-rounded on both adults and juveniles 02Pi flic.kr/p/wwNmaW .

11) Two dark longitudinal lines; one dorso-lateral and one on the periphery of the foot 03Pi flic.kr/p/wNFGy3 which extend forward well beyond dark transverse band 21Pi flic.kr/p/wPVuEt . Lines sometimes faint or absent.

12) Northern Norway to Mediterranean, widespread in Britain. Not Baltic; records in Danish Kattegat are probably misidentified P. sarsii (Lovén, 1846) (Rasmussen, 1973).

 

Similar species

Pusillina sarsii (Lovén, 1846) 28Pi flic.kr/p/vSxcVH

31 Pi flic.kr/p/ynjxoQ & 32 Pi flic.kr/p/xzqyLG

WoRMS accepts P. sarsii as a valid species distinct from P. inconspicua, but several authors express varying degrees of doubt and of difficulty differentiating the two species at some sites. “- - neither the shape of the shell nor the sculpture have much diagnostic value.” (Høisaeter, 2009). “One possibility - - is that P. sarsi is a series of local populations of P. inconspicua, adapted to brackish water.” (Warén, 1996).

1) Protoconch (3 apical whorls) as rest of shell, sometimes dark bronze or faint lilac tinge, but not a purple spot confined to single apical embryonic whorl.

2) Two parallel rows of opaque white, hyphen-like marks in each translucent white cephalic tentacle (K. Jensen, 2015. pers. comm. 2 September); in lateral view one row may conceal other.

3) If present, 6-8 widely-spaced, rounded, shallow costae on apertural view of body whorl but many populations have few or no costate individuals.

4) Maximum height 4 mm. When shells with equal numbers of whorls are compared, P. sarsii is taller than P. inconspicua 29Pi flic.kr/p/wM6eG5 .

5) No filament on penis (Ponder, 1984).

6) Sole similar to P. inconspicua, except opening of posterior pedal gland is dark on (all?) P. sarsii.

7) Opaque white posterior pedal gland stops well-short of edge of sole.

8) Brown and white speckles on the head (Fretter & Graham,1978).

9) Columellar lip slightly reflected, usually leaving an umbilical groove between it and body whorl.

10) Periphery of body whorl rounded on both adults and young, not angulated.

11) Dark peripheral line on foot, when present, may extend forward well beyond proximity of dark, broad, dorsal, transverse band.

12) Norway, Britain, Bretagne, Skagerrak and Kattegat. As Rissoa albella (Lovén 1846) in Denmark (Rasmussen, 1973). NBN has a single possible record in North Sea from Caithness to Kent, species.nbnatlas.org/species/NHMSYS0021055536 (accessed 12 May 2024).

Rissoa parva (da Costa, 1778)

Brown falciform mark (comma) across labial varix on adults 33Pi flic.kr/p/2pQTBSW

; diagnostic when present, but absent from shells less than 2 mm high and from some larger shells.

1) Protoconch various colours, including lilac or purplish, but not confined to single tiny apical embryonic whorl 33Pi flic.kr/p/2pQTBSW & 29Pi flic.kr/p/wM6eG5 .

2) Cephalic tentacles have single medial opaque white line which is sometimes discontinuous 34Pi flic.kr/p/2pQTBPu or missing.

3) If present, 5-6 widely-spaced, often strongly-developed, costae on apertural view of body whorl 33Pi flic.kr/p/2pQTBSW .

4) Maximum height 5 mm.

5) Long, whitish penis, tapering to a filament at tip 35Pi flic.kr/p/2pQZZqa .

6) On equal-sized specimens, foot narrower than on P. inconspicua 30Pi flic.kr/p/wwNbDo .

7) Opaque white posterior pedal gland extends almost to edge of sole 30Pi flic.kr/p/wwNbDo .

8) Head/snout translucent whitish; sometimes has narrow blackish mark and/or a few opaque white marks 34Pi flic.kr/p/2pQTBPu .

9) Short columellar lip reflected onto body whorl, so no umbilical groove visible 33Pi flic.kr/p/2pQTBSW .

10) Periphery of body whorl rounded on adults, angulated on young (4 to 5 whorls).

11) Broad transverse dark band on body spreads onto periphery of sole, but does not extend forwards as a peripheral line 35Pi flic.kr/p/2pQZZqa .

12)

 

Pusillina radiata (R.A. Philippi, 1836)

The precise delimitation of R. radiata is not easy; it is not always separable from other taxa such as R. inconspicua and has remarkable local and geographical variability (Verduin, 1976). It has been suggested (H. Raven, 2023. pers. comm. 9 April) that the live specimens labelled P. inconspicua in this account are Pusillina radiata, a species not on the UK Species Inventory.

1) Apical purple (when present) may extend onto all three whorls of the protoconch 36Pi flic.kr/p/2pNx7hw

2) Cephalic tentacles translucent white with two parallel rows of, opaque white marks in each tentacle 37Pi flic.kr/p/2pNeuHF

3) If present, about 5 to 10 costae visible on apertural view of body whorl 36Pi flic.kr/p/2pNx7hw . About 6 to 11 in Atlantic Iberia (Verduin, 1976). Dark lines in grooves thinner than on P. inconspicua and often obliquely orientated (Verduin, 1976) 37Pi flic.kr/p/2pNeuHF.

4) Maximum height c. 5.3 mm in Mediterranean, 3.9 mm in Atlantic Iberia (Verduin, 1976).

5) No filament on penis (Ponder, 1984).

8) Snout and head often have a broad medial blackish or brown-umber band 38Pi flic.kr/p/2pNZsaR.

9) Columellar lip only slightly reflected, leaving a slight umbilical groove, or none, between it and body whorl (Verduin, 1976).

10) Whorls well-rounded and often sagging on Mediterranean specimens (Verduin, 1976) 37Pi flic.kr/p/2pNeuHF .

11) Two dark longitudinal lines, one dorso-lateral and one on the periphery of the foot, which extend forward well beyond dark transverse band 38Pi flic.kr/p/2pNZsaR . Lines sometimes faint or absent.

12) Black Sea, Mediterranean and Atlantic Iberia to Brittany (Verduin, 1976). Possibly Britain (H. Raven, 2023. pers. comm. 9 April) but not on UK Species Inventory.

 

Habits and ecology

P. inconspicua lives sublittorally to 100 m on fine red algae, muddy sand and sandy gravel. On shores it occurs at LWS on finely branching algae which filter and retain suspended sediment. It lives at full marine salinity down to 20‰ and survives short periods at 15‰. In more brackish sites such as Isefjord, Denmark (14‰ to 22‰) it is replaced by abundant P. sarsii which might be the brackish form of P. inconspicua (Warén, 1996). It often occurs with Rissoa parva, but not on more wave-exposed sites tolerated by that species. It is often abundant in sheltered algal and Zostera environments. Its varied shell-form might be a response to small variations in environment, as is the case for R. parva). It is most numerous when juvenile in late summer. It respires with a ctenidium of stout filaments 25Pi flic.kr/p/wM6fa9.

Locomotion is lubricated by mucus discharged from the anterior pedal mucous gland within the bilaminate anterior edge of the sole 21Pi flic.kr/p/wPVuEt . Turning is facilitated by transverse folding at a constriction in the anterior half of the foot 16Pi flic.kr/p/wPpUYn . The posterior pedal gland 21Pi flic.kr/p/wPVuEt secretes strong threads of mucus which harden on contact with sea water and are used to anchor the snail and act as climbing lines in its movement around algae. P. inconspicua feeds by grazing microphytes, such as diatoms, and algal fragments with its radula from the surface of filamentous algae growing on stones or, sometimes, on bodies of other creatures such as spider crabs (Hyas spp.). A yellow salivary gland on either side of the radula tube 17Pi flic.kr/p/vSoCDu secretes mucus to lubricate the action of the radula and to cement food particles together. It produces oval faecal pellets 16Pi flic.kr/p/wPpUYn & 25Pi flic.kr/p/wM6fa9 ; the colour varies orange-brown or green with its diet. In captivity, faeces were green when it was fed on spinach (Warén, 1996).

Reproduction: it is probably mature when the labial varix is developed, but some populations lack a varix. Fertilization is internal with a long penis 27Pi flic.kr/p/wM6ePE . Spawning is in August and September at Plymouth (Graham, 1988), but in North Wales it is probably in March or April when the population is adult as only juveniles were found in September. Spawning probably varies geographically and with weather as it is regulated by temperature; commencing when the water is 8 to 9ºC and peaking at 10 to 12ºC in laboratory conditions (Warén, 1996). Clear, hemispherical egg capsules are laid on Zostera, debris or shells of other individuals (Graham, 1988). The capsules, 0.35 to 0.65mm diameter, contain a mean each of 20 ova, with a range of 6 to 33. Planktonic veligers are about 0.14mm long when they hatch after four weeks at 8ºC rising to 12ºC over the period, or two weeks at 12 to 13ºC (Warén, 1996). Fretter and Pilkington (1970) illustrated the veliger, and stated “The purple [shell-]apex characteristic of the adult appears after metamorphosis (3 ¾ -whorls).”, but Warén (1996) differed and stated “ - - the veliger larvae can be recognised by the deep and conspicuous purple colour at the point of the spire. The protoconch of three whorls suggests a fairly long period in the plankton enabling wide dispersal and genetic intermixing, so inter-site variation of shell-form is probably the result of sensitivity to environmental variation rather than genetic isolation.

Predators: Pusillina and Rissoa species are the most numerous molluscs in many habitats and an important food source for fish and birds (Warén, 1996). Recently hatched Buccinum undatum were found on filamentous algae with P. inconspicua in Wales and, in captivity, preyed on them 39Pi flic.kr/p/wPpRQD .

 

Distribution and status

P. inconspicua occurs from Northern Norway to the Canary Islands, Azores and into the Mediterranean. It is probably replaced by P. sarsii in the Baltic but there is some confusion over the species there (Wiese & Janke, 2021). GBIF map www.gbif.org/species/5192276 . It is widespread around Britain and Ireland. It is commonest in south and west and scarce or absent at sites in the north-east Irish Sea and North Sea. U.K. map NBN species.nbnatlas.org/species/NBNSYS0000177600

 

Acknowledgements

I am indebted to Jan Light (formerly Marine Recorder of the Conchological Society of G.B. & Ireland) for the generous loan of hundreds of specimens collected and identified by her from thirteen sites in France, Channel Islands, south coast England, Ireland, North Wales and Scotland. The specimens are now at Amgueddfa Cymru - National Museum Wales.

I am most grateful to Kathe Jensen, Ivan Nekhaev, Jakov Prkić, Han Raven and Pero Ugarković for discussion and use of photographs. Any errors or omissions are attributable to me (IFS).

 

Links and references

 

Alder, J. 1844. Descriptions of some new British species of Rissoa and Odostomia. Ann. Mag. nat. Hist. 13 (series 1): 323-328 & plate viii preceding p. 323 . (Original description of species.) archive.org/details/annalsmagazineof13lond

  

Forbes, E. & Hanley S. 1849-53. A history of the British mollusca and their shells. vol. 3 (1853), London, van Voorst. Free pdf at archive.org/stream/historyofbritish03forbe#page/112/mode/2up

Use slide at base of page to select pp. 113 - 117 .

 

Fretter, V. and Graham, A. 1962. British prosobranch molluscs. London, Ray Society.

 

Fretter, V. and Graham, A. 1978. The prosobranch molluscs of Britain and Denmark. Part 4 Marine Rissoacea. J. Moll. Stud. Suppl. 6, 153-241.

 

Fretter, V. and Pilkington, M.C. 1970. Prosobranchia. Veliger larvae of Taenioglossa and Stenoglossa. Conseil international pour l'exploration de la mer. Fiches d'identification. Zooplankton, 129-132.

ices-library.figshare.com/articles/report/Prosobranchia_V...

 

Graham, A. 1988. Prosobranch and pyramidellid gastropods. London, Linnean Society, and Estuarine and Brackish-water Sciences Association.

 

Høisaeter, T. 2009. Distribution of marine, benthic, shell bearing gastropods along the Norwegian coast. Fauna Norvegica 28: 5-106 www.researchgate.net/publication/41758474_Distribution_of...

 

Jeffreys, J.G. 1862-69. British conchology. vol. 4 (1867). London, van Voorst. p.26. archive.org/details/britishconcholog04jeffr/page/26/mode/... .

 

Ponder, W.F. 1984. A review of the Genera of the Rissoidae (Mollusca: Mesogastropoda: Rissoacea). Rec. Aust. Mus. Suppl. 4: 1-221. P. inconspicua images on pp. 28 & 129. media.australian.museum/media/Uploads/Journals/16835/100_...

 

Rasmussen, E. 1973. Systematics and ecology of the Isefjord marine fauna (Denmark). Ophelia, 11, 1-495.

 

United Kingdom Species Inventory (UKSI), the comprehensive database of UK wildlife taxonomy and nomenclature curated by the Natural History Museum, London. www.gbif.org/dataset/dbaa27eb-29e7-4cbb-8eab-3f689cfce116

 

Verduin A. 1976. On the systematics of recent Rissoaof the subgenus Turboella Gray, 1847, from the Mediterranean and European Atlantic coasts. Basteria 40: 21-73. archive.org/details/basteria-40-021-073

 

Warén, A. 1996. Ecology and systematics of the north European species of Rissoa and Pusillina (Prosobranchia: Rissoidae). J. mar. biol. Ass. U.K. 76, 1013-1059. www.researchgate.net/publication/231850423_Ecology_and_sy...

 

Wiese, V. and Janke, K. 2021. Die Meeresschnecken und – muscheln Deutschlands Wiebelsheim, Quelle & Meyer.

 

Glossary

adapical = towards the apex of the shell.

aperture = mouth of gastropod shell; outlet for head and foot.

bifid = divided into two parts by a cleft.

cephalic = (adj.) of or on the head.

coll. = in the collection of (named person or institution, compare with legit).

columella = solid or hollow axial “little column” around which gastropod shell spirals; hidden inside shell, except on final whorl next to lower part of inner lip of aperture where hollow ones may end in an umbilicus or siphonal canal.

 

columellar = (adj.) of or near central axis of spiral gastropod.

columellar lip = lower (abapical) part of inner lip of aperture.

costa = strong rib running across a whorl of a gastropod shell at right angles to direction of coiling and any spiral striae.

 

costae = (pl.) strong axial ribs running across a whorl of a gastropod shell at approximately right-angles to direction of coiling and any spiral striae.

 

= = (adj.) of, or arranged like, costae.

costate = bearing costae.

diatom = microscopic aquatic alga with siliceous cell-walls.

 

ctenidium = comb-like molluscan gill; usually an axis with a row of filaments either side.

 

ELWS = extreme low water spring tide (usually near March and September equinoxes).

embryonic whorl = tiny, initial, apical whorl (sometimes a fraction more than one whorl) of gastropod; formed while embryo in ovum. It plus larval whorls comprise the protoconch. [Some sources confusingly call whole protoconch the embryonic whorls.]

 

falciform = sickle blade shape.

height = (of gastropod shells) distance from apex of spire to base of aperture.

labial varix = especially strong or broad costa (rib) along edge of outer lip of aperture. Sometimes other varices mark positions of previous prolonged pauses in growth.

 

larval whorls = whorls near apex of gastropod shell formed while a planktonic veliger larva. They plus initial apical embryonic whorl comprise the protoconch.

 

legit = (abbreviation; leg.) collected/ found by (compare with coll.)

mantle = sheet of tissue that secretes the shell and forms a cavity for the gill in most marine molluscs.

 

LWS = low water spring tide, two periods of a few days each month when tide falls lowest.

 

metapodium = hind part of the foot.

 

mucus = (noun) viscous, slippery substance secreted by various glands on molluscs.

mucous = (adj.) pertaining to mucus.

opercular = (adj.) of the operculum.

opercular disc = part of foot attached to operculum.

opercular lobe =extension of opercular disc beyond edge of operculum.

operculum = plate of horny conchiolin used to close shell aperture.

palatal lip = outer lip of gastropod aperture.

peristome = entire rim of aperture.

plankton = animals and plants that drift in pelagic zone (main body of water).

protoconch = apical whorls produced during embryonic and larval stages of gastropod; often different in form from other whorls (teleoconch).

 

umbilicus = cavity up axis of some gastropods, open as a hole or chink on base of shell, often sealed over.

 

stria = (pl. striae) very narrow spiral groove.

suture = groove or line where whorls of gastropod shell adjoin.

teleoconch = part of gastropod shell other than the apical embryonic & larval stage protoconch.

 

veliger = shelled larva of marine gastropod or bivalve mollusc which swims by beating cilia of a velum (bilobed flap).

 

Shell-form intermediate between costate and non-costate.

1: protoconch of three whorls; as always, lacks any sculpture.

2-2: three whorls after protoconch with strong costae; produced in summer when optimum growth conditions (Wigham, 1975b).

3: glossy and translucent body-whorl lacking costae; produced in winter/early spring when stress of cold and wave-exposure prevented development of costae. (Wigham, 1975b).

Shell height 3.8 mm. Weymouth. Early April 2012.

 

Rissoa parva (da Costa, 1778)

 

Full SPECIES DESCRIPTION BELOW

Sets of OTHER SPECIES: www.flickr.com/photos/56388191@N08/collections/

 

Synonyms: Turbo parvus (da Costa, 1778); Turboella parva (da Costa, 1778); Rissoa interrupta ( J. Adams, 1800)

Meaning of name: Rissoa = named for G.A. Risso.

parva = (Latin) small

 

Vernacular: foldet tangsnegl (Danish); klein drijfhorentje (Dutch);

 

GLOSSARY below.

 

Shell description

Polymorphic; two main forms, costate 1Rp flic.kr/p/uxFKZK and interrupta (non-costate) 2Rp flic.kr/p/tT8koN , with continuum of intermediate forms 3Rp flic.kr/p/uxy617 .

Usual features of all forms

Up to 5mm high and 3mm broad. Profile generally, moderately tall ; body whorl usually 63-70% shell height, with apical angle 34-44º but varies 25-50º; young profile lower. Whorls well defined by fine suture. Periphery of body whorl rounded on adults, angulated on young (4-5 whorls) 4Rp flic.kr/p/uMPnUQ . Sculpture: apart from costae on some, surface appears smooth, but microscopic spiral lines sometimes detectable, strongest pair of lines may form a cord a short distance below periphery 5Rp flic.kr/p/uxy5iW (only very slight indications of spiral striae found on any shells examined by author). Larval protoconch occupies 2.75-4 apical whorls, always lacks costae; dirty- whitish, brownish, greyish 6Rp flic.kr/p/tTi1dH or tinted lilac. Ground colour, apart from protoconch, dingy-white to horn-colour to chocolate brown, with orange-brown costally-orientated lines varying in number and extent, sometimes absent. White labial varix on mature adults, with groove (not always visible) between varix and edge of aperture 7Rp flic.kr/p/uxy4yQ ; dark brown streak nearest aperture bends sharply in diagnostic falciform (sickle-blade-shape) mark across the varix 6Rp flic.kr/p/tTi1dH & 8Rp flic.kr/p/uxy4h7 . Juveniles lack varix; and falciform mark usually absent on shells below 2mm high 11Rp flic.kr/p/uQoM66 ; on some larger shells falciform mark never develops 10Rp flic.kr/p/tT8hTC . Aperture varies oval to D-shape ; usually 35-47% of shell-height; adapical angle about 90º; lips form a continuous peristome, usually marked brown 1Rp flic.kr/p/uxFKZK & 2Rp flic.kr/p/tT8koN . Curved outer (palatal) lip, thickened by varix on mature specimens, thin and sometimes transparent on juveniles 11Rp flic.kr/p/uQoM66 ; slightly everted at base, angulated where meets columellar lip on young shells , rounded on older ones 12Rp flic.kr/p/uxy3jf . Short columellar lip reflected onto body whorl, so no umbilical groove visible; distinct thin parietal lip 1Rp flic.kr/p/uxFKZK . Internally, aperture white with brown exterior marks visible when shell translucent. Operculum horn-colour, translucent showing dark underlying opercular lobe 13Rp flic.kr/p/uQoLzr , excentric spiral with nucleus near columellar lip when withdrawn 14Rp flic.kr/p/uxy9Hq .

Costate form

Moderately strong shell, old specimens sometimes thickened. Strong, slightly-curved, steep-sided, narrow-topped, white costae cross all of spire-whorls (excepting apical larval protoconch, about 1.5mm height) but only cross adapical two thirds of body-whorl, terminating sub-peripherally (at cord of two spiral striae according to most sources, but not detected on most shells examined by author) 5Rp flic.kr/p/uxy5iW . Typically 8 costae on body-whorl, 12 on penultimate whorl and 12 on the antepenultimate whorl 14Rp flic.kr/p/uxy9Hq . Costate whorls distinctly convex, apical non-costate whorls slightly convex or almost flat 1Rp flic.kr/p/uxFKZK . Microscopic spiral lines sometimes detectable in gaps between costae. Shell-surface usually opaque and matt on and between costae. Brown lines, if any, in grooves between white costae 9Rp flic.kr/p/tT8i85 but often absent 5Rp flic.kr/p/uxy5iW or obscured by debris/growths 15Rp flic.kr/p/tT8gh1 ; frequently only visible brown lines are falciform mark crossing labial varix and spiral band on base of body-whorl 14Rp flic.kr/p/uxy9Hq .

Non-costate, interrupta form

Shell thinner and more fragile than costate form; surface usually fairly glossy and translucent 4Rp flic.kr/p/uMPnUQ & 16Rp flic.kr/p/uxy8G7 . Usually, whorls less convex than on costate form; giving narrower ,sometimes almost straight-sided, profile 4Rp flic.kr/p/uMPnUQ . Orange-brown lines usually, but not always, extend across whole of penultimate and earlier whorls 12Rp flic.kr/p/uxy3jf . Lines vary on body-whorl; they can traverse almost whole whorl from suture to basal spiral band without a break 9Rp flic.kr/p/tT8i85 or with a break at the periphery before continuing off-set from first half 4Rp flic.kr/p/uMPnUQ or with a break and gap at the periphery, and recommence on same course 12Rp flic.kr/p/uxy3jf ; or lines may only traverse adapical part of the body-whorl 8Rp flic.kr/p/uxy4h7 sometimes lines are wavy and variation can be found on the same specimen 2Rp flic.kr/p/tT8koN ; on some shells marks indistinct 10Rp flic.kr/p/tT8hTC .

Intermediate forms

Many gradations between the two forms above of shape, size, solidity, sculpture, glossiness and colour can be found. After smooth protoconch, whorls may be entirely costate or entirely non-costate, or may start as one and change to the other on later whorls 3Rp flic.kr/p/uxy617 & 29Rp flic.kr/p/uQ8TJv .

 

Body description

Ground colour of flesh whitish, translucent to almost transparent. Snout deeply bifid 11Rp flic.kr/p/uQoM66 with longitudinal slit mouth in terminal cleft 17Rp flic.kr/p/uQoKev ; sometimes has medial narrow blackish mark and/or a few opaque white marks 11Rp flic.kr/p/uQoM66 . When pale-yellow salivary glands and bright-yellow buccal mass retracted, snout translucent whitish and head yellow 18Rp flic.kr/p/tT8fro ; when gland and buccal mass pushed forwards, snout yellow and head translucent whitish 19Rp flic.kr/p/uQoJHv . Cephalic tentacles translucent white with single medial opaque white line that may be continuous 8Rp flic.kr/p/uxy4h7 or discontinuous 20Rp flic.kr/p/tThWja . Under high magnification narrow translucent slit may be detected in line 5Rp flic.kr/p/uxy5iW ; occasional specimens, mainly juveniles, lack white line. Slight swelling at base of tentacle 19Rp flic.kr/p/uQoJHv bears black eye with dorsal opaque-yellow patch. Body behind tentacles translucent greyish-white, with yellowish areas 11Rp flic.kr/p/uQoM66 . Dorsal surface of foot translucent greyish-white with broad, dark, transverse band to anterior of mid-point 21Rp flic.kr/p/tT8evA . Anterior quarter of foot has opaque-white, heart-shaped, anterior pedal mucous gland 11Rp flic.kr/p/uQoM66 . Posterior half of foot has opaque-white posterior pedal gland, visible laterally as a white peripheral border 21Rp flic.kr/p/tT8evA . Constriction in foot shows as crease in side when foot contracted 22Rp flic.kr/p/tThVGt ; facilitates transverse folding of narrow foot 5Rp flic.kr/p/uxy5iW ; and medial dividing line on sole allows longitudinal folding. When extended, anterior of sole axe-shaped; bilaminate edge has outlet within for heart-shaped anterior pedal mucous-gland 20Rp flic.kr/p/tThWja . Most of posterior two-thirds of sole occupied by opaque-white posterior pedal mucous-gland with central pore 17Rp flic.kr/p/uQoKev . Dark transverse band on side of foot extends a short way onto sole. Operculum rests on large purple-black/ burnt-umber opercular lobe that extends prominetly like wings 17Rp flic.kr/p/uQoKev and 6Rp flic.kr/p/tTi1dH . Long, translucent-white, dorso-ventrally-flattened metapodial tentacle extends from opercular disc to posterior of foot 13Rp flic.kr/p/uQoLzr or beyond 6Rp flic.kr/p/tTi1dH ; often held in an arch 19Rp flic.kr/p/uQoJHv . Mantle dull-yellow 20Rp flic.kr/p/tThWja to greyish-white 17Rp flic.kr/p/uQoKev with translucent white pallial tentacle at adapical angle of shell-aperture 6Rp flic.kr/p/tTi1dH . Grey-white ctenidium with about 20 short stout filaments, and blackish osphradium, within mantle cavity 23Rp flic.kr/p/tThVtn . Whitish penis, with tapered tip 21Rp flic.kr/p/tT8evA , attached behind right tentacle on males; very long so may be doubled back into mantle cavity 24Rp flic.kr/p/uxy6CC .

 

Key identification features

Rissoa parva

1) Usual maximum height 5 mm.

2) Shell varies thin and unribbed 04Rp flic.kr/p/uMPnUQ to thick and ribbed 05Rp flic.kr/p/uxy5iW & 06Rp flic.kr/p/tTi1dH .

3) Periphery of body whorl rounded on adults, angulated on young (4-5 whorls) 04Rp flic.kr/p/uMPnUQ . No distinct subsutural collar.

4) Brown comma (falciform mark) across labial varix on adults 06Rp flic.kr/p/tTi1dH & 08Rp flic.kr/p/uxy4h7 ; diagnostic, but absent from shells less than 2 mm high 11Rp flic.kr/p/uQoM66 and from some larger shells. Lip not flared.

5) Head/snout translucent whitish; sometimes has narrow blackish mark and/or a few opaque white marks 11Rp flic.kr/p/uQoM66 , but not dorsally dark for whole width between tentacle bases on head, snout and anterior of body.

6) Cephalic tentacles have single medial opaque white line 08Rp flic.kr/p/uxy4h7 ; sometimes discontinuous 20Rp flic.kr/p/tThWja . When magnified, narrow translucent slit may be detected in line 05Rp flic.kr/p/uxy5iW ; occasional specimens, mainly juveniles, lack white line.

7) Yellow eye patches 19Rp flic.kr/p/uQoJHv .

8) Foot is translucent white with a broad, dark, transverse band anterior of the mid-point 21Rp flic.kr/p/tT8evA .

9) Opercular lobe entirely pigmented black or brown 17Rp flic.kr/p/uQoKev .

10) Confusion with R. membranacea is especially likely when on Zostera .

 

Similar species .

Rissoa membranacea (J. Adams, 1800) from north-east Atlantic.

1) Maximum height usually 9 mm in Britain, 13.4 mm recorded in northern Norway.

2) Shell varies thin and unribbed to thick and ribbed 25Rp flic.kr/p/2p6TZdc .

3) Tall, or moderately tall, spire with subsutural collar 25Rp flic.kr/p/2p6TZdc.

4) No comma on labial varix. Entire lip everts into a flared aperture on mature adults 25Rp flic.kr/p/2p6TZdc .

5) Flesh of head and body whitish, translucent, extensively covered by various shades of grey to brown-black pigment dorsally with opaque white spots 26Rp flic.kr/p/2p6SY6C .

6) Cephalic tentacles translucent white with crowded, randomly arranged, opaque, white spots 26Rp flic.kr/p/2p6SY6C .

7) Variably sized, opaque, pure-white, dorsal patch behind each eye 26Rp flic.kr/p/2p6SY6C .

8) Foot is translucent white with some opaque white spots and, dorsally, pale grey and/or pale-brown shading 26Rp flic.kr/p/2p6SY6C .

9) Opercular lobe pale apart from some dark pigment proximally.

10) ELWS, mainly on Zostera in north-east Atlantic.

 

Pusillina inconspicua (Alder, 1844)

1) Maximum size varies locally 1.3 to 3 mm.

2) Shell varies thin and unribbed to slightly thicker with slight ribs 27Rp flic.kr/p/2p6LWXg .

3) Profile varies from squat to fairly tall (spire 23% to 40% of shell-height). Whorls smoothly rounded without angulation 27Rp flic.kr/p/2p6LWXg .

4) Tiny purple apical spot confined to single embryonic whorl; diagnostic when present, but absent from some. Labial varix absent or weakly developed; no brown comma 27Rp flic.kr/p/2p6LWXg .

5) Flesh translucent whitish with some opaque white and yellow patches. Snout often has broad medial blackish or brown-umber band which fills the gap between the tentacles and extends onto the head and body 28Rp flic.kr/p/2p6SXUW .

6) Cephalic tentacles translucent white with two parallel rows of substantial, opaque-white, hyphen-like marks in each tentacle 28Rp flic.kr/p/2p6SXUW .

7) Opaque eye patches vary yellow to whitish.

8) Foot is translucent white with a broad, dark, transverse band anterior of the mid-point.

9) Opercular lobe blackish or brownish at anterior only, projecting posterior of lobe is whitish

10) ELWS, on seaweeds.

 

Habits and ecology

Often abundant, up to 100 000 /m² at LWST on rocky and stony shores; extend from MTL to 15m sublittorally. Lives at full marine salinity down to 20 p.p.t. and survives short periods at 15 p.p.t. On finely branching red algae that filter and retain suspended sediment (and R. parva settling veligers), such as Lomentaria, Plumaria, Ceramium, Callithamnion, Corallina, Plocamium and Cryptopleura; on branching hydroids, in Laminaria holdfasts, and, occasionally, (adults only) under stones. Numbers of R. parva positively correlate with amount of sediment retained; broad algal fronds rarely occupied as do not retain much sediment and do not afford firm grip for adhesive mucous lines or foot suited to grasp filaments. Most numerous in summer e.g. at one site 76 000/m² in summer, 5 000/m² in winter (Fretter & Graham, 1978) . Shell sculpture apparently responds to small changes in environment. Costate-form is a larger % of adult population (those over 1.9mm high) sublittorally and on sheltered shores e.g. on two shores near Plymouth in September 1972, 93.7% at Wembury (sheltered) and 2.3% at Polhawn (exposed). Costate form more dominant in late summer than in late winter on any particular shore e.g. Wembury 93.7% of adults costate in September 1972, fell to 16.7% in February 1973 (Wigham, 1975a). Intermediate individuals with costate early post-protoconch whorls followed by non-costate body-whorl 3Rp flic.kr/p/uxy617 probably settled in summer when growth conditions optimum, so costae formed; and then over-wintered when stress of cold and wave-exposure (perhaps including dislodgement of sediment-food from algae) prevented development of costae . Those with early non-costate post-protoconch whorls followed by costate whorls probably settled in late winter/spring and lived on into following summer 29Rp flic.kr/p/uQ8TJv . Shells sometimes heavily calcified with stony alga, Titanoderma (synonym Lithophyllum) 5Rp flic.kr/p/uxy5iW & 15Rp flic.kr/p/tT8gh1 .

Respiration inhalent current into mantle cavity at left of head has water quality tested by black osphradium before reaching grey-white ctenidium with about 20 stout filaments 23Rp flic.kr/p/tThVtn ; exhalent current passes from mantle cavity at right of head. Locomotion: very active clambering among fine algae and hydroids. Anterior pedal mucous gland discharges within bilaminate anterior edge of sole 20Rp flic.kr/p/tThWja which spreads mucus to lubricate creeping. Medial division of sole allows independent movement on either side, and longitudinal folding 5Rp flic.kr/p/uxy5iW to grip algal strands 7Rp flic.kr/p/uxy4yQ and mucous threads; turning facilitated by transverse folding at constriction in anterior part of foot 30Rp flic.kr/p/tT8dyf . Posterior pedal gland 17Rp flic.kr/p/uQoKev secretes adhesive mucus that is shaped by medial groove on sole into strong threads that harden on contact with sea water and used to anchor the snail and act as climbing lines in its movement around algae or between substrate and pool surface below which it often crawls. Feeds by grazing microphytes (diatoms etc) and algal fragments from surface of algae and hydroids with its radula. Yellow salivary gland on either side of radula tube 18Rp flic.kr/p/tT8fro secretes mucus to lubricate action of radula and cement food particles together. Breeds all year, with summer maximum; up to six generations p.a.. Sexually mature when labial varix developed. Males about 40% of population, smaller than females; long penis develops 24Rp flic.kr/p/uxy6CC when shell reaches 4.5 whorls; fertilization internal. Lens shape spawn capsules, about 0.7mm diameter, containing 6-50 white eggs, each 0.1mm diameter, laid at night on weed or shells of other R. parva. Hatch in three weeks at 12-13ºC into colourless veliger larvae that develop border of orange-red marks on large bilobed velum by 3-whorled shell stage; right velar lobe often larger than left (illustration, full description and differentiation from Pusillina inconspicua pp. 18-20 in Fretter & Pilkington, 1970). After fairly lengthy time in plankton 6Rp flic.kr/p/tTi1dH , settle on fine weed, and metamorphose when shell 2.75- 4 whorls, diameter 0.25 – 0.48mm. Those settling in summer grow at 1mm height per month and live for 3-5months. Autumn settlers over-winter, growing at 0.5mm/month, to breed in spring and die at age 8-9months.

 

Distribution and status

Northern Norway to Canary Islands, Mediterranean and Black Sea. Not Baltic. GBIF map www.gbif.org/species/5192339 . All round Britain and Ireland; scarce or absent in N.E. Irish Sea and coast of East Anglia, U.K.map NBN species.nbnatlas.org/species/NBNSYS0000177721

 

Links and references

Forbes, E. & Hanley S. 1849-53. A history of the British mollusca and their shells. vol. 3 (1853), London, van Voorst. Free pdf at archive.org/stream/historyofbritish03forbe#page/98/mode/2up

Use slide at base of page to select pp. 98 - 103 .

 

Fretter, V. and Graham, A. 1962. British prosobranch molluscs. London, Ray Society.

 

Fretter, V. and Graham, A. 1978. The prosobranch molluscs of Britain and Denmark. Part 4– Marine Rissoacea. J. Moll. Stud. Suppl. 6, 153-241

 

Fretter, V. and Pilkington, M.C. 1970. Prosobranchia. Veliger larvae of Taenioglossa and Stenoglossa. Conseil international pour l'exploration de la mer. Fiches d'identification. Zooplankton, 129-132. Free PDF (enter title in “find a file”) at www.ices.dk/sites/pub/Publication%20Reports/Forms/Marine....

 

Graham, A. 1988. Prosobranch and pyramidellid gastropods. London.

 

Jeffreys, J.G. 1862-69. British conchology. vol. 4 (1867). London, van Voorst. Free pdf at archive.org/stream/britishconcholog04jeffr#page/22/mode/2up . Use slide at base of page to select pp. 23-26.

 

Rasmussen, E. 1973. Systematics and ecology of the Isefjord marine fauna (Denmark). Ophelia, 11, 1-495.

 

Warén, A. 1996. Ecology and systematics of the north European species of Rissoa and Pusillina (Prosobranchia: Rissoidae). J. mar. biol. Ass. U.K. 76, 1013-1059.

 

Wigham, G.D. 1975a. The biology and ecology of Rissoa parva (da Costa). [Gastropoda: Prosobranchia]. J. mar. biol. Ass. U.K. 55: 45-67.

 

Wigham, G.D. 1975b. Environmental influences upon the expression of shell form in Rissoa parva (da Costa). [Gastropoda: Prosobranchia]. J. mar. biol. Ass. U.K. 55: 425-438.

Abstract at journals.cambridge.org/action/displayAbstract?fromPage=on...

 

Current taxonomy: World Register of Marine Species (WoRMS) www.marinespecies.org/aphia.php?p=taxdetails&id=141365

 

Glossary

‰ = (salinity) parts salt per thousand parts water.

abapertural/adapertural = away from/towards the aperture.

abapical/adapical = away from/towards the apex of the shell.

aperture = mouth of gastropod shell; outlet for head and foot.

bifid = divided into two parts by a cleft.

body whorl = most recent and largest whorl of a gastropod shell, which accommodates the withdrawn body, apart from viscera in the spire.

 

buccal mass = anterior of digestive system including a radula, odontophore and muscles.

 

cephalic = (adj.) of or on the head.

columella = solid or hollow axial “little column” around which gastropod shell spirals; hidden inside shell, except on final whorl next to lower part of inner lip of aperture.

 

columellar = (adj.) of or near central axis of spiral gastropod.

columellar lip = lower (abapical) part of inner lip of aperture.

costa = (pl. costae) rib on a whorl of a gastropod shell across direction of coiling and spiral striae. costal = (adj.) of, or arranged like, costae.

 

costate = bearing costae.

diatom = microscopic aquatic alga with siliceous cell-walls.

ctenidium = comb-like molluscan gill; usually an axis with a row of filaments either side.

 

ELWS = extreme low water spring tide (usually near March and September equinoxes).

 

falciform = sickle blade shape.

H. = (height of gastropod shells) distance from apex of spire to base of aperture.

 

labial varix = strong or broad costa (rib) along edge of outer lip of aperture.

 

mantle = (a.k.a. pallium) sheet of tissue which secretes the shell and forms a cavity for the gill.

 

metapodium = hind part of the foot.

metapodial = of or on the metapodium.

MTL= mid tide level

mucus = (noun) viscous, slippery substance secreted by various glands on molluscs.

 

mucous = (adj.) pertaining to mucus.

odontophore = approximately ellipsoid structure containing a pair of cartilaginous bolsters which support the radula. Protruded and retracted like a tongue to operate radula.

 

opercular = (adj.) of the operculum.

opercular disc = part of foot on which the operculum rests.

opercular lobe = extension of opercular disc beyond edge of operculum.

 

operculum = plate of horny conchiolin used to close shell aperture.

 

osphradium = organ for testing inhalant water for particles and/or chemicals.

 

palatal lip = outer lip of gastropod aperture.

pallial tentacle = tentacular extension of the edge of the pallium (mantle).

 

pallium = (a.k.a. mantle) sheet of tissue which secretes the shell and forms a cavity for the gill.

 

parietal lip = upper part of inner side of gastropod aperture, often lacking clear lip structure with just a glaze on side of whorl adapically of columellar lip.

 

pedal = (adj.) of the foot.

periphery = perimeter of the body whorl of a gastropod at its widest.

 

peristome = entire rim of aperture.

plankton = animals and plants that drift in pelagic zone (main body of water).

 

protoconch = apical whorls produced during embryonic and larval stages of gastropod; often different in form from other whorls forming teleoconch.

 

radula = chitinous ribbon of teeth; extended on odontophore to rasp food.

 

stria = (pl. striae) very narrow spiral groove.

suture = groove or line where whorls of gastropod shell adjoin.

teleoconch = entire gastropod shell, apart from apical protoconch.

veliger = shelled larva of marine gastropod or bivalve mollusc which swims by beating cilia of a velum (bilobed flap).

  

Polymorphic 8813 with Basic, 8088 compatible processor, Altair compatible slots. Listed in 1978 at $3250. Today's dollar value, over $10000. More Info

 

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All, thanks for coming, since your here, check out the rest of my photostream . Or just check out my 50 most popular shots. All of my vintage computing photos can be seen here All of my vintage ads can be seen here Thanks, SA_Steve P.S. Also check out my fast food ads from the seventies, targeting African American Consumers

Mais uma vez, muito obrigado ao Marcelo Cazani (Marcazani) pela identificação deste pássaro.

Once more, thank you very much Marcelo Cazani (Marcazani) for the identification of this bird.

 

A text, in english, from Wikipedia, the free encyclopedia:

See at en.wikipedia.org/wiki/American_Kestrel

Jump to: navigation, search

American Kestrel

Conservation status

 

Least Concern (IUCN 3.1)

Scientific classification

Kingdom: Animalia

Phylum: Chordata

Class: Aves

Order: Falconiformes

Family: Falconidae

Genus: Falco

Species: F. sparverius

Binomial name

Falco sparverius

Linnaeus, 1758

Synonyms

 

Cerchneis sparverius

Tinnunculus sparverius

 

The American Kestrel (Falco sparverius) is a small falcon. This bird was (and sometimes still is) colloquially known in North America as the "Sparrow Hawk". This name is misleading because it implies a connection with the Eurasian Sparrowhawk Accipiter nisus, which is unrelated; the latter is an accipiter rather than a falcon. Though both are diurnal raptors, they are only distantly related.

American Kestrels are widely distributed across the Americas. Their breeding range extends from central and western Alaska across northern Canada to Nova Scotia, and south throughout North America, into central Mexico, the Baja, and the Caribbean. They are local breeders in Central America and are widely distributed throughout South America.

Most of the birds breeding in Canada and the northern United States migrate south in the winter, although some males stay as year-round residents. It is a very rare vagrant to western Europe.

The American Kestrel is the smallest falcon in North America—about the size of an American Robin. Like all raptors, the American Kestrel is sexually dimorphic, although there is some overlap within the species. The female ranges in length from 23 to 28 centimeters (9-11 inches) with a wingspan of 53–61 centimeters (21–24 inches) and weighs an average of 120 grams (4.2 ounces). The length of the male varies between 20–25 centimeters (8–10 inches) with a wingspan ranging from 51–56 centimeters (20–22 inches) and weighing an average of 111 grams (3.9 ounces). These subtle differences are often difficult to discern in the field.

The coloration of the feathers, however, greatly varies between the sexes. Males have blue-grey secondary feathers on their wings, while the undersides are white with black barring. The back is rufous in coloration, with barring on the lower half. The belly and flanks are white with black spotting. The tail is also rufous, except for the outer rectrix set, which is white with a black subterminal band.

The back of the female American Kestrel is rufous with dark brown barring. The wings exhibit similar coloration and patterning to the back. The undersides of the females are white with rufous streaking. The tail of the female is noticeably different from the male, being rufous in color with numerous narrow dark brown or black bars. Juveniles exhibit coloration patterns similar to the adults.

In both sexes, the head is white with a bluish-grey top. There are also two narrow, vertical black facial markings on each side of the head; one below the eyes and one on the rear portion of the auriculars. Two black spots (ocelli) can be found on each side of the white or orangish nape. The wings are moderately long, fairly narrow, and taper to a point. While perched, the wingtips are noticeably shorter than the tail tip.

The American Kestrel has three basic vocalizations - the "klee" or "killy", the "whine", and the "chitter." The "klee" or "killy" is usually delivered as a rapid series - "killy, killy, killy, killy" when the kestrel is upset or excited. It is used at the apex of the dive display, during fights with other kestrels, and after unsuccessful hunting attempts.

The "whine" may last as long as one to two minutes and may be single or treble. The more intense the situation, the more likely the "whine" will move toward the treble extreme. "Whines" are given during courtship feeding and copulation. The treble whine is heard from breeding females and fledged hungry young.

The "chitter" is the most frequent vocalization in male - female interactions. Its volume and duration depends upon the stress or excitement of the situation. It is associated with friendly approaches and bodily contact between the sexes during breeding season. Occasionally a "chitter" follows a "whine."

Calling occurs throughout the day. Nestlings at two weeks can produce all three vocalizations. Female kestrels tend to have slightly lower pitched and harsher voices than males.

This bird is apparently not a true kestrel. mtDNA cytochrome b sequence analysis (Groombridge et al. 2002) indicates a Late Miocene split[1] between the ancestors of the American Kestrel, and those of the Common Kestrel and its closest relatives. The color pattern with its large areas of brown is reminiscent of kestrels, but the coloration of the head - notably the black ear patch, which is not found in any of the true kestrels - and the male's extensively gray wings are suggestive of a closer relationship with the hobbies, an informal grouping of falcons of usually average size.

Species such as the Merlin and the Aplomado Falcon are proposed as possible close relatives. Indeed, the Merlin is a highly polymorphic bird and although its grey tail and back are distinctive, certain morphs are the only birds that might conceivably be confused with American Kestrels. Conclusive evidence is lacking, and what can be said at present judging from the fairly noninclusive DNA sequence studies[2] is that the general relationships of the present species seem to lie with a number of rather basal "hobby" lineages, such as the Merlin and Aplomado Falcon mentioned already, or the Red-footed and Amur Falcons - or even the Peregrine Falcon lineage with its large species.

The American Kestrel is not very closely related to any of these groups, although it might be closer to the Aplomado Falcon (and its presumed close relatives, the Bat and Orange-breasted Falcons) than to any other living species (Wink et al. 1998) - an association that is also better supported by biogeography than a close relationship with the exclusively Old World true kestrels. It is nonetheless highly distinct in morphology from any of these and, interestingly, has a syrinx similar to the Peregrine and the hierofalcons[3].

In conclusion, until better evidence is available, it is best considered part of a radiation of falcon lineages that diversified around the North Atlantic at the end of the Miocene. Though several fossils of small falcons arte known from North America at roughly the correct time, the earliest testimony of the American Kestrel lineage is Pleistocene remains of the living species (Brodkorb 1964).

American Kestrels are found in a variety of habitats including parks, suburbs, open fields, forest edges and openings, alpine zones, grasslands, marshes, open areas on mountainsides, prairies, plains, deserts with giant cacti, and freeway and highway corridors.

In addition to requiring open space for hunting, American Kestrels seem to need perches for hunting from, cavities for nesting (either natural or man-made), and a sufficient food supply.

The American Kestrel is the only North American falcon to habitually hover with rapid wing beats, keeping its head motionless while scanning the ground for prey. The kestrel commonly perches along fences and powerlines. It glides with flat wings and wingtips curved upward. It occasionally soars in circles with its tail spread and its wings flat.

This falcon species is not long-lived. The oldest banded wild bird was 11 years and seven months old while a captive lived 17 years. A mortality rate average of 57 percent was found. First year mortality rates have declined since 1945 with a decrease in shooting. Major causes of death include collision with traffic, illegal shooting, and predation by other raptors, including the Red-tailed Hawk, Northern Goshawk, Cooper's Hawk, Peregrine Falcon, Barn Owl, and Great Horned Owl.

In summer, kestrels feed largely on grasshoppers, dragonflies, lizards, mice, and voles. They will also eat other small birds. Wintering birds feed primarily on rodents and birds. The birds characteristically hunt along roadsides from telephone wires, fence posts, trees or other convenient perches when not flying in search of food. When they are flying and looking for food they frequently hover with rapid wingbeats.

Because it feeds on both insects and vertebrates, the American Kestrel maintains fairly high population densities. It has a small breeding home range, from 1.75 square miles (4.5 km²) to 2 square miles (5.2 km²). Territory size has been estimated at 269 acres (1.1 km²) to 321 acres (1.3 km²) with much larger wintering home ranges.

Several hunting techniques are used by the American Kestrel. It will hover over one spot—when prey is sighted the kestrel will partly fold its wings and drop lower once or several times before striking. When the prey disappears the falcon will glide in a semicircle before turning back into the wind to hover again. It will also soar in circles, or figure eights, using the same stooping tactics as when hovering.

The kestrel commonly hunts from elevated perch sites, waiting for prey to move on the ground. The kestrel bobs its head and pumps its tail just before attacking.

Other prey capture techniques include direct pursuit, landing and flushing prey from the ground (especially for grasshoppers)and then taking them in flight, capturing flying insects from an elevated perch, and nest robbing including the burrows of Bank Swallows and the nests of Cliff Swallows. It is also an occasional bat catcher, taking bats from their tree roosts, or striking bats in flight from above or as the bats leave or enter caves. The kestrel will kill and cache food items.

The American Kestrel occasionally robs others of the same species. It has also been known to rob a shrike of its prey. Kestrels sometimes harass other hawks, and even Golden Eagles, in flight.

American Kestrels form pairs in which the bond is strong, tending toward permanence. Returning migrants commonly re-establish territories held the previous year. In one study[citation needed], a pair nested in the same tree for six consecutive years. Nesting occurs from late spring to late summer in North America, with incubation underway by the end of May[4]; in tropical South America the birds breed roughly from June onwards through to September or so[5].

Courtship begins shortly after the male establishes a territory. In early courtship, he may give the "dive display", a series of climbs and dives 33 to 66 feet (10 to 20 m) with 3-5 "klee" notes given near the peak of each climb. He may present the female with food during courtship feeding. He may entice her to the nest site by calling. He may "flutter-glide" toward her with quick and shallow wing beats while carrying food and she may also beg for food by flutter-gliding. The female initiates copulation by bowing with her tail in line with her body or slightly raised.

A cavity nester, American Kestrels will use holes in trees, rock cavities and crevices in cliffs, artificial nest boxes, or small spaces in buildings. The number of suitable breeding cavities limits this species' breeding density. The American Kestrel has adapted well to nest boxes. In one program, nest boxes were fixed to the backs of signs along a freeway thus allowing kestrels to breed in areas formerly devoid of nest sites. Pairs nesting in boxes on poles have much higher nesting success than pairs using boxes on trees. No nest is built inside. In nest boxes sawdust and wood shavings may be a suitable substrate for the eggs. Males and females defend the nest against intruders, with the male maintaining a small core territory and the female defending the nest cavity directly rather the surroundings[5].

Both sexes take turns incubating their eggs, a very rare situation among North American birds of prey where the female usually incubates exclusively. Correspondingly, both sexes develop bare oval patches on each side of their breasts where the warm bare skin can contact the eggs for warming. Eggs hatch 29 to 31 days after being laid.[6] There are from three to seven eggs laid, but four to six are average.[6] The eggs are typically short elliptical in shape, and are white or pinkish-white with an even covering of fine spots and flecks of brown shades, occasionally concentrating as a ring or a cap. They will renest if the first nest fails and have been reported to raise 2 broods per year in some of the southern states.

The young grow very quickly, becoming noisy between day 11 and 14 and assuming adult weight in about 2.5 weeks. The young fledge in 30 to 31 days.[7] [6]Early fledgling behavior varies. Broods typically stay together for a week or two. Some broods remain close to the nest area for a week or two while others travel throughout the parents' home range. Generally, young do not disperse more than 0.6 miles (one km) away from the nest area until two to four weeks old. Young disperse as hunting skills develop. Occasionally groups of older juveniles from various broods join together into flocks.

The American Kestrel can be double-brooded, particularly in the southern United States, in areas of abundant small mammals. Replacement clutches can be laid.

 

Um texto em português:

Falcão-americano ou quiriquiri (Falco sparverius) é um pequeno falcão (23-27 cm de comprimento e 85-140 g de peso). Tem uma ampla área de distribuição: desde o Alasca e Norte do Canadá até à ponta Sul da América do Sul (Terra do Fogo). Tem asas azul acizentadas. O dorso é avermelhado pontuado de preto. A cauda também é avermelhada possuindo uma larga lista preta. Na face possui 2 listas verticais que começam junto aos olhos e seguem para baixo. É um predador de pequeno tamanho, alimentando-se de insetos e microvertrebrados como roedores e pequenos pássaros; ocasionalmente caça morcegos.

Falcão é o nome genérico dado a várias aves da família Falconidae, mais estritamente aos animais classificados dentro do género Falco. O que diferencia os falcões das demais aves de rapina é o fato de terem evoluído no sentido de uma especialização no voo em velocidade (em oposição ao voo planado das águias e abutres e ao voo acrobático dos gaviões), facilitado pelas asas ponteagudas e finas, favorecendo a caça em espaços abertos – daí o fato dos falcões não serem aves de ambientes florestais, preferindo montanhas e penhascos, pradarias, estepes e desertos. Os falcões podem ser identificados, aliás, pelo fato de não planarem em correntes termais, como outras aves de rapina. O falcão-peregrino, especializado na caça de aves médias e grandes em voo, pode atingir 300 km/h em voo picado e é o animal mais rápido da terra. Diferentemente das águias e gaviões, que matam suas presas com os pés, os falcões utilizam as garras apenas para apreenderem a presa, matando-a depois com o bico por desconjuntamento das vértebras, para o que possuem um rebordo em forma de dente na mandíbula superior.

 

Na Idade Média, os falcões eram apreciados como animais de caça acessíveis apenas à elite.

Lucky to meet up with this Rare Winter Visitor on it way back to North.

 

Asian Paradise-flycatcher (Terpsiphone paradisi) "Incei" subspecies

 

(T. p. incei (Gould, 1852) breeds in eastern, northeastern and central China, in the Russian Far East and in the north of Korea; populations occurring in Southeast Asia are non-breeding.)

  

The Asian paradise flycatcher (Terpsiphone paradisi) is a medium-sized passerine bird native to Asia. Males have elongated central tail feathers, and in some populations a black and rufous plumage while others have white plumage. Females are short-tailed with rufous wings and a black head. They feed on insects, which they capture in the air often below a densely canopied tree.

 

With an extremely large range and a large population that appears to be stable, they have been evaluated as Least Concern by IUCN since 2004.

 

In his first description of 1758, Carl von Linné nominated the species Corvus paradisi. Paradise-flycatchers used to be classified with the Old World flycatcher family Muscicapidae, but are now placed in the family Monarchidae together with monarch flycatchers.

  

Characteristics

 

Adult Asian paradise flycatchers are 19–22 cm (7.5–8.7 in) long. Their heads are glossy black with a black crown and crest, their black bill round and sturdy, their eyes black. Female are rufous on the back with a greyish throat and underparts. Their wings are 86–92 mm (3.4–3.6 in) long. Young males look very much like females but have a black throat and blue-ringed eyes. As adults they develop up to 24 cm (9.4 in) long tail feathers with two central tail feathers growing up to 30 cm (12 in) long drooping streamers.

Young males are rufous and have short tails. They acquire long tails in their second or third year. Adult males are either predominantly bright rufous above or predominantly white. Some specimens show some degree of intermediacy between rufous and white. Long-tailed rufous birds are generally devoid of shaft streaks on the wing and tail feathers, while in white birds the shaft streaks, and sometimes the edges of the wing and tail feathers are black.

 

In the early 1960s, 680 long-tailed males were examined that are contained in collections of the British Museum of Natural History, Chicago Natural History Museum, Peabody Museum, Carnegie Museum, American Museum of Natural History, United States National Museum and Royal Ontario Museum. The specimens came from almost the entire range of the species, though some areas were poorly represented. The relative frequency of the rufous and white plumage types varies geographically. Rufous birds are rare in the extreme southeastern part of the species' range. Throughout the Indian area and, to a lesser extent, in China, asymmetrically patterned intermediates occur. Intermediates are rare or absent throughout the rest of the range of the species. In general, long-tailed males are:

 

- predominantly rufous with some white in wings and tail — collected in Turkestan, Kashmir, northern India, Punjab, Maharashtra, Sikkim and in Sri Lanka;

 

- predominantly rufous with some white in wings — collected in Iran, Afghanistan, Baluchistan, Punjab, Kashmir, northern and central India, Rajasthan, Maharashtra, Bihar, Nepal;

 

- predominantly rufous with some white in tail — collected in Punjab, northern and central India, Kolkata, Sri Lanka and in the Upper Yangtse Valley in China;

 

- predominantly white with some rufous in tail and wings — collected in Kashmir, Maharashtra, Sichuan and North China;

 

- predominantly white with some rufous in tail — collected in Maharashtra and Fuzhou, China;

 

- predominantly white with back partly rufous — collected in Punjab and Chennai;

 

- predominantly white with wings and tail irregularly blotched and washed with rufous in places — in the extreme southeastern edge of the range of the species : Alor Island and Sumba;

 

- moulting from rufous into white plumage — collected in North Bihar.

  

Possible interpretations of this phenomenon are : males may be polymorphic for rufous and white plumage colour; rufous birds may be sub-adults; and there may even be two sympatric species distinguishable only in the male.

  

Habitat and distribution

 

Asian paradise flycatchers inhabit thick forests and well-wooded habitats from Turkestan to Manchuria, all over India and Sri Lanka to the Malay Archipelago on the islands of Sumba and Alor. They are vagrant in Korea and Maldives, and regionally extinct in Singapore.

 

They are migratory and spend the winter season in tropical Asia. There are resident populations in southern India and Sri Lanka, hence both visiting migrants and the locally breeding subspecies occur in these areas in winter.

 

According to Linné’s first description Asian paradise flycatchers were only distributed in India. Later ornithologists observed this spectacular bird in other Asian countries, and based on differences in plumage of males described several subspecies, of which the following 14 are recognized today:

 

- T. p. paradisi (Linnaeus, 1758) breeds in central and southern India, central Bangladesh and south-western Myanmar; populations occurring in Sri Lanka in the winter season are non-breeding.

 

- T. p. leucogaster (Swainson, 1838) breeds in the western Tian Shan, in Afghanistan, in the north of Pakistan, in northwestern and central India, in Nepal’s western and central regions; populations occurring in the east of Pakistan and in the south of India migrate towards the foothills of the Himalayas in spring for breeding.

 

- T. p. affinis (Blyth, 1846) inhabits Malaysia and Sumatra.

 

- T. p. incei (Gould, 1852) breeds in eastern, northeastern and central China, in the Russian Far East and in the north of Korea; populations occurring in Southeast Asia are non-breeding.

 

- T. p. insularis (Salvadori, 1887) inhabits the island Nias off the western coast of Sumatra.

 

- T. p. nicobarica (Oates, 1890) inhabits the Nicobar Islands.

 

- T. p. sumbaensis (Meyer, 1894) inhabits the Lesser Sunda Island Sumba.

 

- T. p. floris (Büttikofer, 1894) inhabits the Lesser Sunda Islands Sumbawa, Flores, Lomblen and Alor Island.

 

- T. p. procera (Richmond, 1903) inhabits the island Simeuluë northwest off the coast of Sumatra.

 

- T. p. ceylonensis (Zarudny & Harms, 1912) inhabits Sri Lanka.

 

- T. p. borneensis (Hartert, 1916) inhabits Borneo.

 

- T. p. saturatior (Salomonsen, 1933) breeds in the eastern parts of Nepal and northeastern India, in eastern Bangladesh and northern Myanmar; populations occurring in Malaysia migrate northward for breeding.[9]

 

- T. p. burmae (Salomonsen, 1933) inhabits the central region of Myanmar.

 

- T. p. indochinensis (Salomonsen, 1933) inhabits the eastern regions of Myanmar, Yunnan in the south of China, migrates through Thailand and Indochina to Malaysia, Sumatra and the neighboring islands.

  

Ecology and behaviour

 

Asian paradise flycatchers are noisy birds uttering sharp skreek calls. They have short legs and sit very upright whilst perched prominently, like a shrike. They are insectivorous and hunt in flight in the understorey. In the afternoons they dive from perches to bathe in small pools of water.

 

The breeding season lasts from May to July. Being socially monogamous both male and female take part in nest-building, incubation, brooding and feeding of the young. The incubation period lasts 14 to 16 days and the nestling period 9 to 12 days. Three or four eggs are laid in a neat cup nest made with twigs and spider webs on the end of a low branch. The nest is sometimes built in the vicinity of a breeding pair of drongos, which keep predators away. Chicks hatch in about 21 to 23 days. A case of interspecific feeding has been noted with paradise flycatcher chicks fed by Oriental white-eyes.

  

[Credit: en.wikipedia.org/]

Morelia viridis, the green tree python, is a species of python found in Papua island in Indonesia.

A mostly arboreal species with a striking green or yellow color in adults. The color pattern on this species can vary dramatically from locality to locality. For example, the Aru local is a vivid green with a broken vertebral stripe of white or dull yellow scales, the Sorong local is a bright green with blue highlights and a solid vertical stripe, and the Kofiau local is mostly yellow with varying highlights in white or blue. Cyanomorphs (blue morphs) are also known to occur but are not considered common at this time. Juveniles are polymorphic, occurring in reddish, bright yellow and orange morphs

The gyrfalcon (Falco rusticolus), also spelled gerfalcon, is a bird of prey, the largest of the falcon species. The abbreviation gyr is also seen in the literature. It breeds on Arctic coasts and tundra, and the islands of northern North America, Europe, and Asia. It is mainly a resident there also, but some gyrfalcons disperse more widely after the breeding season, or in winter.

 

Individual vagrancy can take birds for long distances. Its plumage varies with location, with birds being coloured from all-white to dark brown. These colour variations are called morphs. Like other falcons it shows sexual dimorphism, with the female much larger than the male. For centuries the gyrfalcon has been a precious hunting bird, highly valued among the Vikings. Typical prey includes the ptarmigan and water-fowl which it may take in flight. It has also been observed feeding on fish and mammals.

 

The gyrfalcon is a very large falcon, being about the same size as the largest buteos (buzzard hawks). Males are 48 to 61 cm (19 to 24 in) long, weigh 805 to 1,350 g (1.775 to 2.976 lb) and have a wingspan from 110 to 130 cm (43 to 51 in). Females are bulkier and larger, at 51 to 65 cm (20 to 26 in) long, 124 to 160 cm (49 to 63 in) wingspan, and of 1,180 to 2,100 g (2.60 to 4.63 lb) weight.

 

Among standard measurements, the wing chord is 34.5 to 41 cm (13.6 to 16.1 in), the tail is 19.5 to 29 cm (7.7 to 11.4 in), the culmen is 2 to 2.8 cm (0.79 to 1.10 in) and the tarsus is 4.9 to 7.5 cm (1.9 to 3.0 in). The gyrfalcon is larger than the peregrine falcon, which it is known to hunt, and differs from the buzzard in general structure, being unmistakably a falcon with pointed wings, and broader-winged and longer-tailed than the peregrine.

 

The gyrfalcon is a very polymorphic species, so its plumage varies greatly. The archetypal morphs are called "white", "silver", "brown", and "black", though they can be coloured on a spectrum that begins with all-white and ends with very dark. The brown form of the gyrfalcon is distinguished from the peregrine by the cream streaking on the nape and crown and by the absence of a well-defined malar stripe and cap. The black morph has its underside strongly spotted black, rather than finely barred as in the peregrine. White form gyrfalcons are unmistakable, as they are the only predominantly white falcons. Silver gyrfalcons resemble a light grey lanner falcon of larger size. There is no difference in colouring between males and females; and juveniles are darker and browner than the corresponding adults.

 

The black color seems to be sex-linked and to occur mostly in females; it proved difficult for breeders to get males darker than the dark side of slate grey. A color variety that arose in captive breeding is "black chick".

 

This image was taken from the Fred Olsen "Black Watch" as it sailed down the east coast of Iceland in between Akureyri and Reykjavik

Sassafras albidum is easily identified by its polymorphic leaves, with three different leaf shapes on the same tree. This sapling is only a foot tall, so it has about fifty more feet to grow.

pOLymORpHic hUMansCApE by Nandita Kumar

 

"The tiny LCD screens in this interactive piece portray scenes of urban life. The screens react to movement, switching from restful scenes of nature to images of uncontrolled urban sprawl. The artist is intrigued by how urban environments shape our consciousness. She highlights India’s mega-metropoles, where uncontrolled urbanization is exceeding sustainable limits, resulting in slums and impacting negatively on our wellbeing."

 

arsguide.kiasma.fi/en/artwork/nandita-kumar/