Cap 1.0-5.0 cm broad, shallowly to strongly infundibuliform, sometimes merely plano-depressed or umbilicate; margin at maturity deflexed, wavy, thin, entire to eroded; when young, growing around and incorporating twigs and debris; surface reddish-brown, rust-brown, to chestnut-brown, usually faintly-zonate, velutinate at the disc, elsewhere silky to coarsely, appressed fibrils, if the former, then somewhat shiny in appearance; context thin, 0.5-2.0 mm thick, colored like the cap surface, blackish with 3% KOH; odor and taste untried.
Pore layer adnate to subdecurrent, cinnamon-brown to tan; pores 2-3/mm, elongate at first, angular and t\hin-walled in age; tubes 1-2 mm deep, concolorous with the pore surface.
Stipe 1.0-3.0 (4.0) cm long, 1.0-3.0 mm thick, central, round to compressed, solid, equal except enlarged at the base, the latter frequently fused with adjacent fruiting bodies; surface finely velutinous, rust-brown to dull orange-brown; context leathery when fresh, rigid at maturity, colored like the stipe surface.
Spores 6.5-8.5 x 4.5-5.0 µm, elliptical to oblong-elliptical, smooth, thin-walled, inequilateral, slightly bean-shaped in profile, hilar appendage inconspicuous, a single guttule usually present, weakly dextrinoid in Melzer's reagent; spore deposit not seen.
Scattered, gregarious, to cespitose, in soil and humus in mixed or conifer woods; fruiting winter and spring along the coast; if present in the Sierra Nevada mountains, uncommon.
This terrestrial polypore occurs commonly in the San Francisco Bay area under Monterey pines (Pinus radiatus). It is recognized by rusty-brown, often clustered fruiting bodies. The caps are usually faintly-zoned cap with appressed fibrils, in certain light sometimes appear to glisten. Coltricia perennis, found in the Sierra Nevada and elsewhere, differs in having a more distinctly-zoned cap, and a matted-tomentose surface. Compared to Coltricia cinnamomea, the cap colors are more muted--cinnamon-brown, tan, ochre to greyish. Additionally the tube layer of Coltricia perennis tends to be more decurrent than in C. cinnamomea. For look-alikes, see "Comments" under Coltricia perennis