All white, with a ring on the stalk and a large, saclike cup around the stalk’s base (sometimes hidden underground). Grows on the ground in mixed woods and in grass near trees. June–November. Cap curved to flat with central swelling; smooth margin; dull to shiny white; texture smooth, tacky when wet. Gills narrow to broad; spacing close; white; gills free or slightly attached. Stalk sometimes enlarging toward the base; white; texture cottony to shaggy; with a ring. Universal veil white, leaving a large, saclike cup around the base of the stalk; partial veil leaves a large, white, skirtlike ring on the upper part of the stalk. Spore print white. Spores magnified are nearly round to round, smooth.
Lookalikes: Meadow mushroom has pink gills that turn brown, a brown spore print, and lacks a basal, saclike cup. Other amanitas look similar. In the past, Amanita virosa was considered a close lookalike, but DNA testing has shown that it is not found in the United States.