Solitary or subfasciculate on decaying wood and stumps of various deciduous trees. Early summer to autumn. A widespread, mainly nemoral, but not a very common species. Not documented from the UK. Widely distributed in Norway, although not very common.

Pileus 15-60 mm across, parabolical to convex, with or without a low umbo, flattening with age, translucent-striate, sulcate, hygrophanous, at first very dark brown or black-brown, soon fading to grey-brown to grey, sometimes nearly whitish, the margin paler to almost white. Lamellae 25 - 30 reaching the stipe, ascending, narrowly adnate, smooth to veined, pale grey to white, sometimes tinged pinkish or incarnate. Stipe 25-80 x 3-8 mm, equal, terete, straight to curved, hollow, fragile, finally innate-fibrillose and with a satiny sheen, pruinose above and glabrous farther below, pale bluish white or greyish white when very young, gradually turning white, the base usually darker, more or less densely covered with white fibrils. Odour nitrous, but often weak or even absent. Taste +/- mild, slightly raphanoid or farinaceous.

Basidia 30-36 x 7-9 μm, slender-clavate, 2-spored or 4-spored. Spores (basidia 4-spored) 8-11.2 x 5.2-7 μm, Q 1.2 - 1.7, Qav ~ 1.5 or (basidia 2-spored)11.6-14.8 x 6.7-8.1 μm , pip-shaped, smooth, amyloid. Cheilocystidia 40-110 x 9-22 x 0-4.5 μm, fusiform, lageniform, conical, subcylindrical, clavate, smooth, apically broadly rounded or gradually to more abruptly tapered into a shorter or longer neck. Pleurocystidia similar. Lamellar trama dextrinoid, brownish vinescent in Melzer's reagent. Hyphae of the pileipellis 2-4.5 μm wide, smooth, not embedded in gelatinous matter. Hyphae of the cortical layer of the stipe 3-4.5 μm wide, smooth, not gelatinized, with caulocystidia 6-9 μm wide, smooth to somewhat branched. Clamps absent or present in all tissues.

Microphotos of cheilocystidia and pileipellis.

Mycena niveipes usually occurs early in the season (May - July), but it can also be found in the autumn. It can usually be identified on account of the satiny sheen on the stipe and the microscopic features: the large, smooth cystidia and the smooth hyphae of the pileipellis and the cortical layer of the stipe

It is a member of sect. Fragilipedes, and young specimens may be confused with M. algeriensis. Generally the latter species is darker in older specimens, the stipe is elastic-cartilaginous, and the hyphae of the pileipellis are embedded in gelatinous matter. M. niveipes may also sometimes resemble M. galericulata, a species of sect. Mycena, but that species can easily be distinguished on account of completely different cheilocystidia and diverticulate hyphae of the pileipellis.

According to Maas Geesteranus (1988a: 266) M. niveipes occurs both in a 2-spored and a 4-spored form, both either with or without clamps. This rather exceptional situation should be further studied using molecular tools.

Further images on the web:

Michael Krikorev