Cycas revoluta
The family of the Cycadaceae includes only the kind Cycas, restricted to tropical regions. The particular distribution of these plants, which show some important discontinuities and disjunctions, testifies their character wreck. It is, in fact, of a very ancient group, which reached its zenith in the Cretaceous. The general appearance of these plants remember the palm trees, with large leaves, pinnate or bipinnate, spirally arranged apex of the drum, where they form a crown. Alongside the assimilation leaves are also not green leaves, fluffy, whose function is to protect the gems. The radical party are secondary rootlets with bulges coralliformi hosting colonies of blue-green algae, such as Nostoc and Anabaena, and bacteria. The Cycadaceae include only species dioecious, with male flowers (microsporofilli), the scaly or peltati shape, inserted spiral about an axis; they carry on the underside pollen sacs in varying numbers and often grouped in sori. The female flowers (macrosporofilli) are found in large numbers in the upper part of the stem with the appearance of pinnate leaves, with the ovules, in number of 4-8, inserted at the margin. The pollen grains give rise to 2 anterozoidi ciliates that reach the room pollen swimming. After fertilization the outside of the seed coat that surrounds the ovum becomes fleshy and the seed ends with the resemble a drupe. The embryo has two cotyledons.
Cycas revoluta
The family of the Cycadaceae includes only the kind Cycas, restricted to tropical regions. The particular distribution of these plants, which show some important discontinuities and disjunctions, testifies their character wreck. It is, in fact, of a very ancient group, which reached its zenith in the Cretaceous. The general appearance of these plants remember the palm trees, with large leaves, pinnate or bipinnate, spirally arranged apex of the drum, where they form a crown. Alongside the assimilation leaves are also not green leaves, fluffy, whose function is to protect the gems. The radical party are secondary rootlets with bulges coralliformi hosting colonies of blue-green algae, such as Nostoc and Anabaena, and bacteria. The Cycadaceae include only species dioecious, with male flowers (microsporofilli), the scaly or peltati shape, inserted spiral about an axis; they carry on the underside pollen sacs in varying numbers and often grouped in sori. The female flowers (macrosporofilli) are found in large numbers in the upper part of the stem with the appearance of pinnate leaves, with the ovules, in number of 4-8, inserted at the margin. The pollen grains give rise to 2 anterozoidi ciliates that reach the room pollen swimming. After fertilization the outside of the seed coat that surrounds the ovum becomes fleshy and the seed ends with the resemble a drupe. The embryo has two cotyledons.