On riparian herbaceous monocot stalks, e. g. Juncus, Scirpus, Glyceria. Summer to autumn. Widespread and at least in places common, e.g Denmark and the Netherlands. In Norway rather common along the coast in Southern parts of the country, but also recorded in Trøndelag (Røros).

Pileus 2-8 mm, covered with a separable, gelatinous pellicle (not easy to observe), hemispherical to convex, becoming plano-convex, more or less umbonate, sulcate, translucent-striate, glabrous, at first grey-brown, fading towards pale grey to grey-white. Lamellae 10-12 reaching the stipe, ascending, fairly broad, free or attached to a pseudocollarium, white or greyish white, the edge separable as a gelatinous thread. Stipe 5-20 x 0.1-0.5 mm, entirely pubescent, glabrescent, except for the base, watery white, springing from a white-pubescent basal disc, +/- striate, 1 mm broad. Odour none.

Basidia 18-32 x 8-9 µm, clavate, 4-spored, with sterigmata 1-7 µm long. Spores 7.5-11 x 4-5(-6.0) µm, Q = 1.5-2.1, Qav = 1.9, pip-shaped to subcylindrical, smooth, non-amyloid. Cheilocystidia 18-55 x 2.7-9 µm, subcylindrical, clavate or irregularly shaped, apically with one or 2-3 necks, or with several coarse, variously shaped excrescences 1-11.5 x 0.5-3.5 µm. Pleurocystidia absent. Lamellar trama dextrinoid, vinescent brown in Melzer's reagent. Hyphae of the pileipellis 1.5-5 µm wide, branched and much entwined, smooth but upper surface diverticulate with excrescences 1-7 x 0.5-1.5 µm, embedded in gelatinous matter. Hyphae of the cortical layer of the stipe 1.2-3 µm, smooth, caulocystidia 15-49 x 5-16 µm, clavate, cylindrical or subfusiform, smooth. Clamp connections present at all tissues.

Mycena bulbosa is readily identified by the growth on herbaceous stalks in wetland areas and the stipe springing from a prominent basal disc. Maas Geesteranus (1983: 414) placed it in a section of it's own, namely sect. Bulbosae Maas Geest. Another species with a basal disc, Mycena stylobates, can occasionally be found in the same type of habitat, but it can be distinguished because of the amyloid spores. In addition the Cheilocystidia and the Caulocystidia are differently shaped.

Microphotos of the pileipellis