Cap 1.0-4.0 cm broad, convex, expanding to nearly plane, occasionally centrally depressed or with a low umbo; margin incurved in youth, translucent striate, becoming decurved to raised in age; surface, glabrous, hygrophanous, dull reddish-brown to orange-brown, drying to pinkish-buff or pale-tawny; context 1.0-2.0 mm thick at disc, firm, cream-buff, gradually tinged like the cap when cut or injured; odor and taste farinaceous.
Gills adnexed to notched, close, relatively broad, up to 3.0 mm wide, at first cream-colored, darkening slightly with age; lamellulae in three to four series.
Stipe 2.0-4.0 cm long, 2.0-5.0 mm thick, stuffed, brittle, more or less equal, the base sometimes pointed; surface of apex pruinose, pallid to buff, elsewhere glabrous, colored like the cap; partial veil absent.
Spores 6.5-7.5 x 4.0-5.0 µm, elliptical to tear-shaped in face-view and warted; angular in end-view; hilar appendage conspicuous, inamyloid; spore print pinkish-buff.
Scattered to gregarious on humus and soil under conifers in montane regions in the spring; fall and winter along the coast in mixed hardwood-conifer woods; uncommon.
This seldom collected member of the Entolomataceae is recognized by a collybioid stature, orange-brown to reddish-brown cap (when moist), farinaceous odor, and pinkish spores. Macroscopically it resembles Gymnopus dryophilus, a common early season mushroom, found as the species epithet suggests, under oaks. The latter is similar in color and hygrophanous, but lacks a translucent-striate cap margin, farinaceous odor, and possesses white rather than pinkish spores. Other Rhodocybe (all are now in the genus Clitopilus) species occasionally encountered include Rhodocybe nuciolens, larger than R. nitellina with a pinkish-brown, non-striate cap, lacking a farinaceous odor, known primarily from coastal woodlands, and Rhodocybe caelata, a small greyish to greyish-brown species with a matted-tomentose, often depressed cap. Several collections of this nondescript mushroom have been made along the coast north of San Francisco and in the Sierra Nevada.