Mycena abramsii (Murrill) Murrill

Mycologia 8: 220 (1916).

Mycena abramsii

© A. Aronsen
Telemark, Tinn, Langefonn 11 July 2011


Growing in small groups or subfasciculate on debris of various deciduous trees or on moss-covered trunks of living trees. Occasionally also found on coniferous debris (Picea). Occuring typically in early summer, but can also be found in the autumn. Widespread in Norway, also found in alpine sites. See the records in The Norwegian Mycological Database.

Pileus 10-40 mm across, parabolical to conical, flattening with age, with or without a low umbo, translucent-striate, sulcate, pruinose, glabrescent, grey-brown to somewhat darker brown. Lamellae 15-27 reaching the stipe, ascending, narrowly adnate to adnate, smooth to somewhat rugulose to strongly veined, becoming dorsally intervenose, white to greyish with paler edge. Stipe 30-90 x 1-2(-4) mm, fragile, equal or somewhat broadened downwards, terete, hollow, smooth, pruinose above, glabrous below, becoming shiny when drying, when very fresh exuding a watery fluid when incised, pale grey, dark grey-brown to dark sepia brown, usually somewhat darker below and whitish grey at the apex, pallescent with age, the base densely covered with long, coarse, flexuous, whitish fibrils. Odour more or less nitrous, or sometimes absent.

Basidia 25-36 x 8-9 μm, clavate, 4-spored. Spores 7.5-13 x 4-6.5 μm, Q = 1.6-2.1, Qav = 1.8-1.9, elongated to cylindrical, smooth, amyloid. Cheilocystidia 25-55 x 10-14 μm, fusiform, clavate, subcylindrical, more rarely sublageniform, usually apically drawn into a slender neck or occasionally with two or more necks. Pleurocystidia similar. Lamellar trama dextrinoid, brownish vinescent in Melzer's reagent. Hyphae of the pileipellis 2-4 μm wide, covered with scattered to crowded, simple to branched, excrescences 2-10 x 1-2 μm, which tend to become gelatinized. Hyphae of the cortical layer of the stipe 2-2.5 μm wide, sparsely diverticulate, terminal cells hard to find, uniflated, diverticulate. Clamp connections present in all tissues.

Microphotos of cheilocystidia

Microphotos of the hypae of the pileipellis

Microphotos of spores

Mycena abramsii is a member of the large section Fragilipedes (Fr.) Quél., where it takes a position close to section Lactipedes (Fr.) Quél.. The watery exudation produced by incising the stipe is a distinct feature of this species, but is rarely demonstrable in specimens only a few hours after collecting, and in fresh specimens that have become somewhat dry.

It is not always easily distinguished from other members of the section. The cheilocystidia, which apically usually are drawn into a slender neck, and the somewhat elongated spores are useful identification characters. The smell is variable and has been recorded differently by different collectors.

M. aetites (Fr.) Quél. differs in having shorter but broader spores and differently shaped cheilocystidia, as well as in the habitat; lawns meadows and grassland. In M. leptocephala (Pers.) Gillet the hyphae of the cortical layer of the stipe are smooth, the terminal cells are generally conspicuously inflated, and the cheilocystidia are somewhat differently shaped.

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Further images on the web:

Mykoweb

Mushroomobserver

Michael Krikorev

 

 

© Arne Aronsen 2002-2015