Cap 0.5-2.0 cm broad, convex, becoming convex-depressed to infundibulate; margin incurved, then decurved to plane, sometimes appearing scalloped in age; surface glabrous, striate-sulcate to near the disc, vinaceous-brown, hygrophanous, fading to pinkish-tan, finally pale-tan; context thin, pallid; odor and taste mild.
Gills long decurrent, close to subdistant, pale-pink, fading to pinkish-cream, pallid at maturity; lamelluae up to three-seried.
Stipe 1.0-2.5 cm long, 1-3 mm thick, pliant, more or less equal, straight or bent, hollow in age; surface pruinose, becoming glabrous, colored like the cap, i.e. vinaceous to pinkish-brown, paler in age, often nearly tan; whitish tomentum at base; partial veil absent.
Spores 8.0-10.5 x 4.0-5.5 µm, ellipsoid, smooth, inamyloid, contents granular, hilar appendage prominent; spore print white.
Scattered to gregarious in open areas, e.g. along trails and in sparse grass, often in moss; fruiting along the coast from mid-winter to spring; exact distribution unknown but probably widespread; occasional, locally common.
Typical of the genus, Omphalina pyxidata is a small, white-spored mushroom with an infundibulate cap, striate-sulcate margin, and decurrent gills. Its vinaceous to pinkish-brown hues are an important distinguishing feature. In age the cap may fade to a nondescript tan, but the gills and stipe usually retain some pinkish color. Other California Omphalinas (s.l.) include Omphalina postii with a bright-orange to reddish-brown cap, cream-yellow gills and a reddish-brown stipe; Omphalina ericetorum, (also known as Phytoconis ericetorum, but now called Lichenomphalia umbellifera), is the fruiting stage of a basidiomycete lichen, has a light-brown to yellow-brown cap, cream-colored gills, and red-brown to yellow-brown stipe; Omphalina epichysium (now known as Arrhenia epichysium) is the most somber-colored member of the group, the cap, stipe, and gills greyish-brown. Besides color it differs from the above in being truly lignicolous.