Clitocybe nuda

Common Name: None.
Description: Cap 4-15 cm broad, broadly convex, flat with uplifted margin in age, sometimes with a low knob, smooth, without hairs, dry, various shades of violet to violet-gray to cinnamon with buff color in age, margin inrolled at fist. Stalk 3-6 cm long, 10-25 mm thick.
Habitat: Single but more often numerous, occasionally cespitose in needle duff or deep leaf litter under hardwoods and conifers or even in piles of leaves, lawn grass, or around compost piles.
Edible: Very good.

Source: Mushrooms of North America by Orson K. Miller, Jr.