Synonym: Marasmius villosipes Cleland
Misapplied name: Collybia fuscopurpurea
Cap 1.5-3.0 cm broad, convex, expanding to nearly plane, sometimes depressed to umbilicate at the disc; margin incurved, becoming decurved, often striate-wrinkled approx. half the distance from the margin to the disc, sometimes torn or eroded at maturity; surface smooth, hygrophanous, dark-brown fading to dingy tan; flesh pallid, thin; odor and taste mild.
Gills adnexed, sometimes seceding and appearing free, close, moderately broad, at first greyish-brown becoming dull light-brown to buff, the edges lighter than the faces.
Stipe 2-5 cm tall, 1-3 mm thick, slender, pliant, straight to curved, round, flattened to grooved, more or less equal; surface variable: when fresh and moist, medium brown, pubescent, the hairs sometimes appressed, when dry, dingy-buff at the apex, greyish-brown at the base, more conspicuously pubescent; veil absent.
Spores 6-8.5 x 3.5-4 µm, elliptical, smooth, nonamyloid; spore print whitish.
Gregarious to clustered under conifers, often fruiting in large masses on needle duff, occasionally in wood chips; fruiting from late fall to mid-winter.
Until recently, this ubiquitous litter decomposer was thought to be an undescribed species, but Desjardin, Halling and Perry have shown that it is the same as Marasmius villosipes described by Cleland from under introduced Monterey pine in Australia in 1934. Gymnopus (Marasmius) villosipes is believed to be a California native. Thus it has the unusual distinction of being first described from material introduced into another country. Gymnopus villosipes is distinguished by a hygrophanous, wrinkled, dark-brown cap that fades to dingy tan, mild odor, a pubescent stipe, and tendency to produce large gregarious fruitings under conifers. Dried (shriveled), faded, sporocarps can often be rehydrated and appear fresh with a dark brown cap color.