Gregarious among needles under Juniperus
communis or on open lawns. Autumn. M. parca has been found at three localities
in the South East of Norway. Robich (2003: 277-280) reported
it from Italy. Recently it has also been recorded from Denmark. See records in The
Norwegian Mycological Database.
Pileus 7-30 mm
across, conical, parabolical, convex to plane, often with
recurved margin with age, usually with a prominent, obtuse
umbo, sulcate, translucent-striate, hygrophanous, at first
pruinose, glabrescent, brownish black to dark brownish grey
with a blackish centre, fading to grey, margin grey to whitish. Odour indistinctive, raphanoid or experienced as nitrous. Taste strong, nitrous or somewhat
rancid. Lamellae 17-26 reaching
the stipe, ascending, narrowly adnate, with or without a
short tooth, somewhat rugulose and dorsally intervenose
with age, grey to dark grey with pallid to white edge. Stipe up to 60 x 3 mm, straight to somewhat curved, terete, with
age sometimes flattened, and occasionally somewhat fissured
lengthwise, hollow, equal or somewhat broadened below, fragile,
glabrous, becoming shiny, apically pale grey, brown to grey-brown
below, becoming entirely grey, the base covered with long,
coarse, flexuous, whitish fibrils.
Basidia c. 27 x
7 µm, clavate, 4-spored, clamped, with sterigmata
c. 7 µm long. Spores 7-9 x 4.5-6 µm, Q 1.3-1.7, Qav ~ 1.6, pip-shaped, smooth, amyloid. Cheilocystidia 38-68(-80) x 0-16 x 2.5-5 µm, forming a sterile band, lageniform, smooth. Pleurocystidia similar, not numerous. Lamellar trama dextrinoid, brownish vinescent in Melzer's reagent. Hyphae
of the pileipellis 2.7-4.5 µm wide, not very densely covered
with cylindrical, curved to flexuous excrescences 4.5-18
x 1.8-2.2 µm. Hyphae
of the cortical layer of the stipe 1.6-3.5
µm wide, smooth, terminal
cells scarce, 45-65 x 5.5-7 µm,
clavate. Clamp connections present at all tissues (but clamps sometimes hard to detect).
Microphotos of cheilocystidia
Microphotos of hyphae of the pileipellis
Mycena parca is a member of the large
and complex section Fragilipedes (Fr.) Quél.
It is closely related to the widely distributed species Mycena leptocephala (Pers.: Fr.) Gillet, from which it can be distinguished
only by a close microscopic examination. The type is described
as a non-smelling, grey species. That was probably influenced
by dry weather. Later records have shown that it is a much
darker species, more or less with a nitrous odour. It can normally be
separated from M. leptocephala by the stipe, which
is conspicuously glabrous. The large, lageniform cheilocystidia should also be a good character.