Amanita phalloides, known in English as Death Cap, is a mushroom of the Amanita genus.
It is a large and distinctive fungus, usually with a cap from 5 to 15 cm across smooth yellow to brown with a green tinge and a partial veil, white fine gills and a white 4 to 18 cm stipe (stalk) with a ring and a swollen volva (base). It is found primarily in Europe but also in northern America, underneath oaks and other hardwoods, usually in autumn to early winter. The fungus is mycorrhizal and beneficial to plants.
As the common name suggests it is highly poisonous, responsible for the majority of fatal mushroom poisonings worldwide, notably through its similarity to Volvariella volvacea. It contains two types of toxins spread throughout the mushroom, phallotoxins (phalloidin, phalloin, phallisin, phallicidin) and amanitins (amatin, amanin, amanullin). The toxin most responsible for the deadly effects of the Death Cap is alpha-amantin. The poison particularly affects the liver and kidneys; frequently the only treatment for Death Cap poisoning is liver transplant.
Asian immigrants in North America and Europe often mistake the Death Cap for the edible straw mushroom (Volvariella volvacea) due to its similarity in appearance. This is a leading cause of mushroom poisoning in the United States.
