Cap 2.0-4.0 mm broad, at first hemispherical, becoming convex to flattened-convex, the disc sometimes sub-umbilicate; margin incurved in youth, decurved at maturity; surface translucent-striate/sulcate from margin to disc, the latter pale grey, elsewhere pallid, coated with white, sugar-like granules, these frequently inconspicuous with age; context thin, membranous, translucent-white, unchanging when cut; odor and taste mild.
Gills adnexed to notched, sometimes forming a collar-like structure near the stipe, closely spaced when young, subdistant in age, relatively broad, whitish, edges minutely fringed (use hand lens); lamellulae up to two-seried.
Stipe 0.4-1.0 cm long, < 1.0 mm thick, filiform, round, hollow, equal except for a swollen, disc-like base; apex whitish, translucent, glabrous, lower portion pale grey, lustrous with sparse hairs, becoming more densely hairy near the basal disc; partial veil absent.
Spores 8.0-10.5 x 4.0-6.0 µm, broadly ellipsoid to oblong-ellipsoid, smooth, thin-walled, contents granular, hilar appendage not conspicuous, faintly amyloid; spores white in deposit.
Scattered to gregarious on fallen branches of hardwoods and conifers; common after periods of wet weather; fruiting throughout the mushroom season.
This tiny white Mycena is easily recognized when young by a cap coated with sugar-like granules, and a stipe with a swollen disc-like base. The cap granules becomes less distinct with age but remnants can usually be found with a hand-lens. Similar Mycenas include M. alphitophora and M. stylobates. Mycena alphitophora resembles M. adscendens in having a granular cap, but the stipe base is not swollen or disk-like. Somewhat larger and sturdier is Mycena stylobates. This species does have a basal stipe disc, but lacks cap granules.