Cap 0.7-1.5 (2.0) cm broad, obtuse-conic to convex, plano-convex in age, with or without a low umbo; margin decurved when young, inconspicuously fringed (use hand lens), nearly plane at maturity; surface glabrous, lubricous when moist, hygrophanous, dark-brown to mahogany-brown, translucent-striate to near the disc, fading to buff-brown; context thin, less than 1.0 mm, pallid; odor mild, taste slightly astringent or bitter.
Gills adnate to subdecurrent, sometimes descending as lines in the apical region of the stipe, close, relatively broad, up to 2.0 mm, edges minutely fringed and lighter than the faces, at first dull tan, becoming dingy medium-brown; lamellulae in up to three series.
Stipe 1.0-3.0 cm long, 1.0-2.0 mm thick, spindly, straight to sinuous, more or less equal, stuffed, becoming hollow in age; surface covered with scattered whitish fibrils over a tan to medium-brown background, whitish mycelium at the base; partial veil fibrillose, inconspicuous, leaving fragments on the immature cap or upper portion of the stipe.
Spores 7.0-9.5 x 4.5-6.0 µm, elliptical to almond-shaped in face-view, slightly inequilateral in profile, smooth, thick-walled, with an apical germ pore and inconspicuous hilar appendage. Spore print dark greyish-brown according to Guzman (1983).
Scattered to gregarious in moss beds; mostly montane; fruiting fall and spring; occasional to locally common.
Unknown, not hallucinogenic according to the literature.
As the species name suggests, this Psilocybe is found primarily at higher elevations. It is recognized by a strongly hygrophanous cap that is initially dark-brown and lubricous with a striate margin, fading to pale-tan when dry. Like many Psilocybes, it has a gelatinous, separable cuticle (pellicle). The tendency to fruit in moss beds is also distinctive.