Fly Agaric

Amanita muscaria, commonly known as the fly agaric or fly amanita or simply red toadstool, is a basidiomycete fungus of the genus Amanita. Its name may come from its historical use to kill flies or from the effects it causes (a medieval belief held that flies could enter the head and cause madness). It is a distinctive, large, white-gilled mushroom typically featuring a bright red cap covered with white warts. The complex genetic diversity of A. muscaria suggests that it is a species complex. It is a widely distributed mushroom native to temperate and boreal forests of the Northern Hemisphere, now also naturalised in the Southern Hemisphere, forming symbiotic relationships with various trees and spreading invasively in some regions.

Abridged excerpt from the Wikipedia article Amanita muscaria, by its authors, under the CC BY-SA 4.0 licence.