Cespitose or fasciculate on decaying wood of both conifer and deciduous trees. Autumn. Recorded over most of the covered area, but nowhere considered common, and in part red listed. In Norway most records from the south-east and Trøndelag, recorded north to Finnmark. Almost exclusively on Picea.

Pileus 10-45 mm across, conical to somewhat campanulate or convex to plano-convex, mostly without an umbo, glabrous, translucent-striate, sulcate, hygrophanous, pale grey to dark grey or greyish brown or dark brown with paler margin, sometimes with a reddish shadow in the centre, with age developing reddish brown spots and finally often becoming entirely dark red-brown with paler margin. Lamellae 20-23 reaching the stipe, elastic-tough, ascending, narrowly to broadly adnate, with or without a decurrent tooth, dorsally intervenose, pale grey to grey with white edge, with age developing red-brown spots. Stipe 40-80 x 1-5 mm, straight to somewhat flexuous, tough, equal, terete or sometimes flattened and fissured lengthwise, hollow, glabrous, often rooting, the base densely covered with wolly white fibrils; at first with whitish apex, grey to grey-brown below, becoming darker, brown to red-brown from the base, with age becoming entirely red-brown. Odour indistinctive. Taste indistinctive, not farinaceous.

Basidia 25-40 x 6-10 um, slender-clavate, 4-spored, with sterigmata 4-8 um long. Spores 7.5-10 x (4.5-)5-6 um, Q 1.5-2, Qav ≈ 1.6, pip-shaped to ellipsoid, amyloid. Cheilocystidia (10.5-)18-40 x 4.5-18 um, forming a more or less sterile band, clavate to somewhat irregularly shaped, covered with fairly few unevenly spaced, coarse, simple to much branched, straight to curved or flexuous, cylindrical excrescences, one or two of which may be longer than the others, up to 20 um long. Pleurocystidia absent. Lamellar trama dextrinoid. Hyphae of the pileipellis 1.5-5 um wide somewhat gelatinized, mostly smooth or covered with scattered warts or cylindric excrescences 1-10 x 1-1.5 um, terminated by mostly diverticulate cells. Hyphae of the cortical layer of the stipe 1.8-3 um wide, smooth to sparsely diverticulate with excrescences 1-4.5 x 0.5-1.5 um, terminal cells up to 5.5 um wide and somewhat more densely diverticulate. Clamp connections present in all tissues.

Microphotos of cheilocystidia and pileipellis

Microphotos of cheilocystidia

Microphoto of cheilocystidia

Mycena maculata is a member of sect. Mycena. It is not always easy to identify. The epithet is somewhat deceptive as it may give the false impression that unspotted specimens belong to another species. As one can se from the description above, particularly younger specimens can appear entirely without red-brown spots.

The colour of the pileus is usually relatively dark. Then it may be confused with dark forms of M. galericulata. In the latter, however, the hyphae of the pileipellis are much more diverticulate and tending to form dense masses, the spores are larger than those of M. maculata, and the terminal cells of the stipe cortex are either absent or very hard to find. In addition the lamellar edge is entirely sterile in M. galericulata, while in M. maculata there are tracts of basidia scattered along the lamellar edge. According to my experience M. galericulata also has a fairly strong farinaceous taste.

Another species resembling unspotted M. maculata is M. hemisphaerica. According to Maas Geesteranus (1992) it deviates from M. maculata on account of some minor microscopic differences as having the cheilocystidia forming a continuous sterile band, while they are forming a discontinous sterile band in M. maculata. In addition the stipe cortex of M. hemisphaerica is devoid of terminal cells, and the excrescences of the cheilocystidia are differently shaped.

Mycena atrochalybaea Huijsman, known from Switzerland and Italy, is also very close to M. maculata, and one wonders whether it really is a distinct species. Robich (2003: 492) mentioned some differences: The number of lamellae reaching the stipe is larger in M. atrochalybaea than in M. maculata, the hyphae of the cortical layer of the stipe are smooth in the former, and the terminal cells are smooth and not enlarged.

The differences can be tabulated as follows:

One should notice that M. polygramma also can become spotted with red-brown stains at the lamellae and elsewhere, and, hence, may show some resemblance to M. maculata. M. polygramma, however, is a member of sect. Fragilpedes, and a completely different species, usually with a silvery grey, longitudinally grooved stipe, smooth to coarsely diverticulate cheilocystidia, broader spores, and very much branched hyphae of the pileipellis. Mycena inclinata lacks the vinaceous tinges, has a crenulate pileus margin and a strong spicy smell.

It has been suggested that the present concept of M. maculata comprises two different species. The distribution and substrate of the taxon strongly indicate a mixed species concept. The more boreal conifer associated taxon would appear to be darker and larger than the primarily oak inhabiting southern population. This should be investigated with molecular methods.