Tricholomopsis platyphylla

Common Name: None.
Description: Cap 3-12 cm across, hemispherical soon expanded to almost flat with a sunken center and sometimes a low umbo, margin often splitting in age; dark gray-brown with an ochraceous tint, sometimes lighter; somewhat streaky surface from radial fibers sometimes forming minute scurfy scales toward the margin. Stem 60-120 by 10-30 mm high and wide.
Habitat: singly or scattered on hardwood stumps, logs, debris, and pieces of buried wood. Common. Found widely distributed in eastern North America west of Ohio, and occasionally reported on the West Coast.
Edible: Edible.

Source: Mushrooms of North America by Roger Phillips.