Amanita \Am`a*ni"ta\, n. [NL. See {Amanitine}.] (Bot.) A genus of poisonous fungi of the family {Agaricace[ae]}, 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). [Webster 1913 Suppl.]