Amanita phalloides , commonly known as the death cap, is a deadly poisonous basidiomycete fungus, one of many in the genus Amanita. Widely distributed across Europe, A. phalloides forms ectomycorrhizas with various broadleaved trees. In some cases, death cap has been accidentally introduced to new regions with the cultivation of non-native species of oak, chestnut, and pine. The large fruiting bodies (mushrooms) appear in summer and autumn; the caps are generally greenish in color, with a white stipe and gills.
Coincidentally, these toxic mushrooms resemble several edible species (most notably caesar’s mushroom and the straw mushroom) commonly consumed by humans, increasing the risk of accidental poisoning. A. phalloides is one of the most poisonous of all known toadstools.
It has been the subject of much research, and many of its biologically active agents have been isolated. The principal toxic constituent is α-amanitin, which damages the liver and kidneys, often fatally.