Mycena pura

Common Name: None.
Description: Cap 2-5 cm across, convex with a broad umbo; margin sometimes split in large, mature specimens; color varying from shades of purplish lilac or pink to yellowish or white; radially lined at margin when moist, paler when dry. Stem 40-100 by 2-8 mm high and wide.
Habitat: scattered to gregarious on humus in hardwood and coniferous forests. Common. Found throughout North America.
Edible: Traditionally eaten, but use with caution.

Source: Mushrooms of North America by Roger Phillips.