A genus of poisonous fungi of the family Agaricaceæ, characterized by having a volva, an annulus, and white spores. The species resemble edible mushrooms, and are frequently mistaken for them. Amanita muscaria, syn. Agaricus muscarius, is the fly amanita, or fly agaric; and Agaricus phalloides is the death cup (or death cap).
The genus Amanita contains about 600 species of agarics including some of the most toxic known mushrooms found worldwide. This genus is responsible for 95% of the fatalities resulting from mushroom poisoning, with the death cap accounting for 50% on its own. The most potent toxin present in these mushrooms is alpha-amanitin.