Cap 1.5-4.5 cm broad, conic, then convex, finally nearly plane with a low umbo, margin striate, sometimes upturned in age; surface smooth, moist, hygrophanous, color varying from purple, lilac, greyish-lilac, rose, pinkish-grey to nearly white, fading in age; flesh thin, pale lilac; taste and odor mildly of radish.
Gills adnexed, close, moderately broad, intervenose, colored like the cap but lighter, e.g. dingy-buff-lilac when young to pinkish-buff in age, edges paler than the faces.
Stipe 2-6 cm tall, 0.2-.7 cm thick, hollow, fragile, equal or tapering to an enlarged base, the latter hairy; surface pruinose at the apex, otherwise smooth, concolorous with the cap, e.g. lilac fading to pinkish-lilac in age; veil absent.
Spores 6-8.5 x 3-4 µm, smooth, elliptical, amyloid; spore print white.
Single to scattered in mixed hardwood/conifer woods; fruiting from late fall to late winter.
Questionable. Reported as edible, at least in small amounts, but too unsubstantial to collect for the table.
This Mycena is not only large for the genus but also attractive with a pleasing usually lilac-colored, striate-margined cap. Other identifying characters are the gills which are lighter than the cap and have pallid edges, a hollow, fragile stipe, and a radish-like odor and taste. Mycena pura is one of several purple-colored mushrooms in the Bay Area. It is most likely to be confused with Inocybe geophylla var. lilacina, but that species lacks a striate margin, has a green corn odor and brown spores. Laccaria amethysteo-occidentalis is a larger mushroom, more distinctly purple when fresh and has a fibrous, not smooth stipe. Finally, there is Clitocybe nuda and several lilac-colored Cortinarius species, but these are significantly more robust.