Agaricus subperonatus

The cap of Agaricus subperonatus is 5 to 12 centimeters across. When young it is hemispherical, opening with age to convex and flat. The surface is covered with numerous pressed-down fibrous scales of brown to reddish-brown on a paler background, especially dense in the center. The scaly brown cap gives the mushroom a stout look.

The hymenophore is gilled. The gills are free, not attached to the stem, and very crowded. Their color changes with age: in young mushrooms they are pale pink or grayish-pink, then darken to chocolate-brown and almost black. The spore print is dark brown. Pinkish young gills distinguish this mushroom from the white-gilled poisonous amanitas.

The stem is cylindrical, fairly thick, white, 4 to 9 centimeters tall. Its defining feature is a dense ring, below which the stem is covered with bands of small brown scales that look like a pulled-on "stocking" or shoe — hence the name. When cut, the flesh may turn faintly red. There is no volva at the base.

The flesh is white, fairly dense, and when cut slowly turns red or brown, especially at the base of the stem. The taste is mild, pleasant and mushroomy, typical of cultivated button mushrooms. Reddening (rather than bright yellowing) is a useful feature that distinguishes this species from the poisonous yellow stainer.

The smell is pleasant and mushroomy, with no sharp notes. If, however, the mushroom smells of ink or carbolic, and the flesh turns bright yellow when cut, it is the poisonous yellow stainer, and you must not take it.