Solitary to gregarious among grass and moss
in open areas or in mixed woods, or on tree stumps, on decayed
and often moss-covered wood of both deciduous and coniferous
trees, or on fallen branches. Spring to late autumn. Widely distributed in Norway. See the records in The Norwegian Mycological Database.
Pileus up to 25
mm across, at first ovoid-cylindrical, then conical or parabolical
to campanulate, without or with small to large umbo, flattening
with age, translucent-striate, sulcate, pruinose, glabrescent,
hygrophanous, at first fairly dark brown, often blackish
brown, with whitish margin, then very dark grey to paler
grey, or dark grey-brown to almost black-brown, pallescent
when drying, turning grey-brown, the margin paler to whitish.
Lamellae 14 - 26 reaching the
stipe, ascending, narrowly to fairly broadly adnate, occasionally
decurrent with a short tooth, becoming rugulose to veined,
dorsally intervenose, fairly dark grey-brown to grey, paler
with age, the edge concolorous with the sides or paler to
whitish. Stipe 20-65 x 1-2.5 mm,
hollow, fragile, equal or somewhat broadened below, terete,
straight to curved, minutely puberulous all over, glabrescent
for the greater part except at the apex, shiny, dark brown,
grey-brown to grey, darker below, paler above, the apex
generally greyish, but in younger specimens often bluish-black,
the base densely covered with long, coarse, flexuous, white
fibrils. Odour nitrous.
slender-clavate, generally 4-spored (but
8-11.2 x 4-5.8 µm, Q 1.6-2.1, Qav ~1.8, pip-shaped, smooth, amyloid.
27-80 x 9-19 µm, forming a sterile band, fusiform,
lageniform, subcylindrical, clavate, apically
broadly rounded or mucronate or gradually to more
abruptly passing into a longer or shorter neck, sometimes
with a few excrescences. Pleurocystidia
present. Hyphae of the pileipellis
covered with cylindrical, simple to branched excrescences
which may form dense masses and tend to become somewhat
gelatinized. Hyphae of the cortical layer
of the stipe
smooth or occasionally
with a few coarse excrescences just below the terminal
4.5-20 µm wide, often
much inflated, variously shaped and branched, usually
curved outwards or constituting caulocystidia. Clamp connections
generally present at all tissues (but see remark).
Microphotos of caulocystidia
Microphotos of hypahae of the pileipellis
Mycena leptocephala is a member of
sect. Fragilipedes (Fr.)
Quél. and belongs to a group of quite similar looking
species with or without a nitrous smell. M.
aetites (Fr.) Quél. lacks the nitrous smell,
the hyphae of the cortical layer of the stipe are diverticulate,
and the terminal cells are unobtrusive, not inflated and
easily overlooked. M. austera
Aronsen can be distinguished on account of the absence of
clamps, the conspicuously inflated terminal cells of the
pileipellis, and the differently shaped caulocystidia. M.
parca Aronsen is very close, but the cheilocystidia
are generally more lageniform, the hyphae of the pileipellis
are generally unbranched and the terminal cells of the stipe
cortex are scarce and fairly narrow. The rare and poorly known M.
aronsenii Maas Geest. can be separated on account
of the smaller spores and the peculiar hyphae of the cortical
layer of the stipe.
Among the species not found in Norway, M.
fragillima A.H. Sm. seems to be very close, and in
my opinion the arguments for keeping it as a separate species
are rather weak. Maas Geesteranus (1992: 246) pointed out
that M. fragillima had been found on fern debris,
that its stipe was described as very pale watery grey, and
that it was very fragile, and stated that these characters
do not fit with M. leptocephala. I do not agreee.
According to my experience this is within the variation
of this very variable species.
Mycena leptocephala is a variable
species but usually easy to identify. In the field it can
be confused with several other nitrous-smelling species
(e.g. M. stipata, M. abramsii, M.
parca) but is readily identified on account of the
smooth hyphae of the cortical layer of the stipe and the
conspicuously shaped terminal cells of these hyphae, combined
with the diverticulate hyphae of the pileipellis.
is generally 4-spored and clamped, but Smith (1947: 243)
mentioned to have found 2- and 3-spored forms. According
to Maas Geesteranus (1992: 259) one of these collections
proved to be devoid of clamps. Maas Geesteranus (1991b)
also reported a 2-spored and clampless collection from Germany
and I have myself seen both 2-spored and 4-spored collections
devoid of clamp connections!
I suspect M. leptocephala to comprise more than one phylogenetic species, and this should be investigated by molecular methods.
Further images on the web:
Pilze Pilze Galerie