Summary:
Typicae (Smith), Section Fragilipedes (Maas Geesteranus). Mycena leptocephala is gray with an alkaline odor, and habitat on the ground as well as on wood. Other features include a somewhat hygrophanous, moist, striate cap that is pruinose at first, subdistant gills, a stem that is white-pruinose becoming polished except at the top, and microscopic characters. Smith describes another species, Mycena kauffmaniana, the type of which according to Maas Geesteranus is Mycena leptocephala, and the other supporting material of which is from at least two other species. Mycena metata sensu J. Schroet., Kuehner, a synonym of this species, is not to be confused with Mycena metata (Fr.) Kummer which is equivalent to Mycena metata (Fr.) Quel.

Cap:
1-3(4)cm across, obtusely conic with margin pressed to stem at first, becoming conic to convex or bell-shaped; fuscous to blackish fading to light gray; hoary-pruinose becoming bald, moist, translucent-striate becoming sulcate [grooved], (Smith), up to 2cm across, conic or parabolic to bell-shaped, without or with umbo, flattening with age; somewhat hygrophanous, very dark gray, sepia brown with a grayish shade, "dark brown to almost black-brown with a violaceous sheen when very young (caused by pruinosity)", also at times of a somewhat warmer brown at center, pallescent [becoming paler] when drying, turning gray-brown, the margin paler to whitish; dry but slightly lubricous when wet, at first pruinose, becoming bald, sulcate [grooved], translucent-striate, (Maas Geesteranus)

Flesh:
thin, fragile; grayish, (Smith), thin, watery sepia brown to whitish, (Maas Geesteranus)

Gills:
ascending-adnate, with decurrent tooth, subdistant (18-27 reaching stem), narrow, 1-2 tiers subgills; pallid or cinereous [ash-gray], edges pallid; edges even, (Smith), ascending, fairly broadly adnate, occasionally decurrent with a short tooth, 14-26 reaching stem, up to 0.3cm broad, moderately ventricose [broader in the middle], becoming rugulose [finely wrinkled] to veined, also interveined; fairly dark, sepia-tinted gray-brown, paler when old, the edges colored as faces or paler to whitish, (Maas Geesteranus)

Stem:
(2)4-6(12)cm x 0.1-0.2cm, equal, very fragile, hollow; usually bluish black at first (darker than cap) but soon dingy brownish gray then pallid or cinereous; densely white-pruinose over all becoming polished and translucent, base nearly bald to white-strigose [with coarse hairs], (Smith), 2-6cm x 0.1-0.2cm, equal or widening somewhat in lower part, fragile, hollow, round in cross-section, straight or curved in lower part; gray-brown to sepia brownish, darker in lower part, paler in upper part, sometimes with a lilaceous tinge when very young; smooth, shiny, minutely puberulous [downy] all over, becoming bald for the greater part (except at top), "the base more or less densely covered with long, coarse, flexuous, whitish fibrils", (Maas Geesteranus)

Odor:
weakly alkaline (stronger if crushed), (Smith), nitrous (by some collectors experienced as of potato skin or alkaline), but fugacious [fleeting] and sometimes seemingly absent, (Maas Geesteranus)

Taste:
acidulous (Smith), rarely recorded, once stated to be disagreeable, (Maas Geesteranus)

Microscopic spores:
spores 7-10 x 4-6 microns, broadly elliptic, amyloid; basidia usually 4-spored, (2- and 3-spored forms found on which the spores measured 11-12 x 6-6.5 microns or 8-10 x 3.5-4.5 microns); pleurocystidia scattered, rare or absent, 30-44 x 9-13 microns, "variable in shape, fusoid-ventricose to clavate, the apex forked in some", the clavate ones occasionally with two or three finger-like projections, cheilocystidia numerous, similar to pleurocystidia, (Smith), spores (8.1)9.4-11.2 x 4.5-6.5 microns, pip-shaped [elliptic], smooth, amyloid; basidia generally 4-spored, 28-36 x 7-9 microns, narrowly clavate, clamped; pleurocystidia to cheilocystidia similar if present, cheilocystidia 27-80 x 9-17 x 0-5 microns, forming a homogeneous sterile band, fusiform, lageniform, subcylindric, clavate, clamped, apically broadly rounded or mucronate [abruptly tipped from a flatter surface], "or gradually to more abruptly passing into a longer or shorter neck or again with a few excrescences"; terminal cells of outer layer of stem 4.5-20 microns wide, "often considerably inflated, variously shaped and branched, less frequently cystidia-like, usually curved outwards or apically geniculate, constituting the caulocystidia and all manner of structures intermediate between caulocystidia and terminal cells"; in general with clamp connections although one of Smith''s variants with less than 4-spored basidia proved not to have clamp connections, (Maas Geesteranus)

Spore deposit:
white (Breitenbach)

Notes:
Mycena leptocephala has been found at least in WA, OR, NS, ON, MB, south to CA and NC, including MD, ME, MI, and NY, (Smith). It has been reported from BC (Gamiet) and there are many collections from BC at the University of British Columbia. It is found in Europe and Iceland, (Maas Geesteranus). Breitenbach(3) give the distribution as North America, Europe (including Switzerland), Asia, North Africa, and Australia.

EDIBILITY

Synonyms and Alternate Names:
Mycena chlorinella (J.E. Lange) Singer
Mycena kauffmaniana A.H. Sm.