Cap 1.0-2.5 cm broad, at first hemispheric, sometimes with a low umbo at the disc, becoming convex, broadly so in age; margin incurved, in age decurved to occasionally plane, fringed with evanescent whitish scales when young; surface glabrous, subviscid, translucent-striate when young and fresh, hygrophanous; color reddish-brown to dingy yellowish-brown, fading in age; context thin, colored like the cap, unchanging when cut or bruised.
Gills adnate, subdistant, relatively broad, pale grey when young, becoming greyish-brown, finally purple-brown.
Stipe 1.5 - 5.0 cm long, 1.0-3.0 mm thick, equal, dry, straight to sometimes curved at the base; surface often squamulose when young, becoming fibrillose, whitish to dingy yellow-brown, not bruising blue; partial veil absent or if present, evanescent leaving fine scales on the young pileus and/or in a superior ring zone.
Spores 11-14 x 7-9 µm, ellipsoid, smooth; spore print purple-brown.
Scattered to clustered on horse and cow dung; fruiting after rains during the winter months.
This small dung dweller is recognized by a sticky, reddish-brown to dull yellowish-brown cap which when young is edged with cottony white fibrils and is typically translucent-striate. Unlike most Psilocybe species, P. coprophila does not bruise or discolor blue, with the exception of a few reports of bluing mycelium. Psilocybe coprophila also differs from most members of the genus in not being hallucinogenic (according to Stamets, it contains neither psilocybin or psilocin). Psilocybe coprophila is most likely to be confused with Stropharia semiglobata, another dung dweller with a viscid cap, but the latter is more yellowish, lacks a translucent striate margin even when young, and has a slimy, not dry stipe. Other mushrooms found on dung include Panaeolus and Coprinus species. Species of Panaeolus can be separated by dry, not viscid caps and distinctive mottled gills, while Coprinus species typically dissolve into an inky liquid in age.