Talasmyren

This is a place I walk past every day. In the summer you can smell the scent of the mire. It's a very special scent and I would like to know where it comes from. Do you know what I'm talking about? It appears suddenly sometimes when you are close to mires and it only takes a moment before the nose/brain gets used to it and then its gone. So if anyone knows what causes the scent please let me know.

Done