AMANITA. The amanitas include some of the most showy representatives of the Agaricineae or mushroom order of fungi (q.v.). In the first stages of growth, they are completely enveloped by an outer covering called the veil. As the plant develops the veil is ruptured; the lower portion forms a sheath or volva round the base of the stem, while the upper portion persists as white patches or scales or warts on the surface of the cap.

Amanita muscaria. 
A, the young plant. g, the gills.
B, the mature plant. a, the annulus, or remnant of velum partiale.
C, longitudinal section of mature plant. v, remains of volva or velum universale.
p, the pileus. s, the stalk.

The stem usually bears an upper ring of tissue, the remains of an inner veil, that stretched from the stem to the edge of the cap and broke away from the cap as the latter expanded. The presence of the volva, and the clear white gills and spores, distinguish this genus from all other agarics. They are beautiful objects in the autumn woods; Amanita muscaria, the fly fungus, formerly known as Agaricus muscarius, being especially remarkable by its bright red cap covered with white warts. Others are pure white or of varying shades of yellow or green. There are sixteen British species of Amanita; they grow on the ground in or near woods. Several of the species are very poisonous.