Solitary or in small groups on decaying
vegetable matter as small twigs, conifer needles, rotten
logs, fallen leaves, grass stems and fallen coniferous cones. Summer to autumn. Not uncommon under Salix in alpine sites. Records in The Norwegian Mycological Database.
Pileus 3-8 mm
across, hemispherical to broadly conical, sometimes becoming
plano-convex, occasionally somewhat centrally depressed,
translucent-striate, sulcate, pubescent to conspicuously
setose, particularly at the centre, grey to grey-brown.
Lamellae 12-15 reaching the
stipe, ascending, narrowly adnate, free or forming a pseudocollarium,
white to pale grey. Stipe 10-50 x 1-2(-3) mm, hollow, straight, terete, equal, entirely puberulous,
grey; springing from a ca. 1 mm wide grey, grey-brown to whitish grey, pubescent basal disc. Odour
Basidia 15-22 x 6.5-8 μm, clavate,
4-spored. Spores 7.5-10.5 x 3.8-4.7
μm, Q = 1.7-2.3, pip-shaped, smooth, non-amyloid. Cheilocystidia
11.5-30 x 5.5-13.5 μm, clavate or fusiform, apically
broadly rounded or gradually drawn into one or two or three
slender necks, or with one single neck or two-three necks abruptly emergent from the surface of the cheilocystidium, usually unbranched but occasionally branched, straight, curved or flexuous, 4.5-33 x 1 μm. Pleurocystidia
absent. Lamellar trama dextrinoid. Hyphae of the pileipellis 2-11 μm wide, branched,
covered with straight to curved, branched to unbranched, cylindrical excrescences 2-12 x 1 μm, embedded in gelatinous
matter, with long, very thick-walled, one-celled
hairs (pileo-setae) up to 200 μm long arising from
the pilei trama. Hyphae of the cortical layer of the stipe 2-3.5 μm wide, smooth. Caulocystidia
similar to the pileo-setae, up to 250 μm long, thick-walled to solid, with bulbous
base. Clamp connections generally absent (but see remark).
Mycena aciculata represents the common,
widely distributed, temperate Northern Hemisphere species
misidentified in the literature as M. longiseta.
M. longiseta is a species restricted to southeast
Asia. A commentary on the confusion around the species concept
of M. longiseta was published by Desjardin &
Horak (2002). M. aciculata differs from M.
longiseta primarily in having inamyloid spores, distinctive
cheilocystidia, more strongly gelatinized pileipellis tissue,
shorter pileosetae, thick-walled caulocystidia and basal
disc cystidia, and in lacking pileus marginal cystidia (Desjardin
et al. 2002).
Mycena aciculata is readily identified
on account of the setae at the pileus and the stipe. The
small basal disc is not always easy to see.
According to Maas Geesteranus (1992: 25-26) Mycena aciculata is devoid of clamps. That is my experience as well, but collections
A 4/92 and A 28/93 showed scattered clamps at the septa
of the basidia and the cheilocystidia.
Robich (2003c) described a new species from
Italy, Mycena setulosipes, that was separated from
M. aciculata on account of a more brownish pileus, a larger number of lamellae
reaching the stipe, absence of basal disc, larger and almost
subglobose spores, absence of pileosetae, and presence of
Microphotos of hyphae of the pileipellis
Microphotos of cheilocystidia
Microphoto of pileo-seta
Further images on the Internet:
Mushroom observer 1
Mushroom observer 2