Cap 4.0-8.0 (10) cm broad, obtuse-conic to convex, eventually plano-convex; margin incurved, then decurved, sometimes upturned and wavy in age; surface moist, not viscid, glabrous to minutely tomentose, cream-colored, becoming pinkish-tan, tawny-brown to rusty-brown toward the disc, often spotted these colors at maturity; context soft, white, unchanging, up to 1.0 cm thick at the disc; odor mild, fungal; taste slightly bitter.
Gills adnexed, close, relatively narrow, up to 0.5 cm broad, the edges uneven, cream-colored, in age pale-tan, frequently with tan to rust-brown spots; lamellulae in up to five series.
Stipe 4.0-8.0 cm tall, 0.5-1.0 (1.5) cm thick, more or less equal, the base usually pointed and partially rooted; stipe round to flattened, readily splitting, hollow in age; surface dry, whitish, conspicuously longitudinally striate, tending to become spotted like the cap; partial veil absent.
Spores 5.5-7.0 x 4.5-5.5 µm, subglobose to ovoid (elliptical in some varieties), smooth, thin-walled, hilar appendage inconspicuous; some spores dextrinoid in Meltzer's reagent; spores cream to tinged pink in deposit.
Solitary, in small groups, or clustered on well-rotted conifer logs or lignin-rich soils in montane regions in the spring; also in coastal forests during the mid-winter months; uncommon.
Inedible, usually bitter.
Rhodocollybia maculata is a cream-colored mushroom that, as the species epithet suggests, becomes spotted in age. The mottling, usually tawny to rusty-brown, is most obvious on the cap but can also be seen on the gills and stipe. Other fieldmarks include a fruiting habit on rotting conifer wood, and a conspicuously striate stipe. Several varieties have been described differing in color and spore shape. Variety maculata, described above, appears to be the most common in California. Rhodocollybia maculata's closest relatives, Rhodocollybia badiialba, Rhodocollybia oregonensis, and Rhodocollybia butyracea vary in cap color from tan, reddish-brown to dark vinaceous-brown, but lack spots. In the Sierra Nevada, Rhodocollybia maculata should be compared with two snowbank species, Mycena overholtzii and Megacollybia platyphylla. Both occur on rotting wood, the former in clusters, the latter usually in small groups. Mycena overholtzii has a light-grey to tan, striate-margined cap with a conspicuously pubescent stipe base, while Megacollybia platyphylla has a dark grey to brown cap and broad gills. Neither species is spotted in age.