Solitary or in small groups among mosses
and lichens and low shrubs (e.g. Salix repens,
but also Juniperus communis) on (always calcareous?)
sand. Probably not yet found in Norway.
Pileus 5-15 mm, hemispherical to plano-convex, with age becoming somewhat depressed or broadly umbonate, the margin somewhat crenulate, not or little sulcate, translucent-striate, delicately pruinose at first, glabrescent, slightly lubricous when moist, hygrophanous, dark sepia brown to grey brown. Lamellae 12-20 reaching the stipe, ascending or arcuate, broadly adnate and quite deeply decurrent, grey, whitish towards the edge. Stipe 15-40 x 0.5-1.5 mm, hollow, firm, equal, terete, straight, smooth, pruinose, glabrescent for the greater part, slightly lubricous when moist, grey above, pale brown below, the base often slightly bulbous and covered with long, coarse, whitish fibrils. Odour none (also said to be raphanoid when crushed). Taste none or raphanoid or somewhat bitter, not farinaceous.
Basidia 25-35 x 8-9 µm, clavate, 2-spored, with sterigmata up to 8 µm long. Spores 10.6-13(-14) x 5-6.5(-7.2) µm, Q=1.8-2.5, Qav ~ 2.1, pip-shaped to almost cylindrical, smooth, amyloid. Cheilocystidia 21-32 x 5-12 µm, not mixed with basidia, clavate to more or less irregularly shaped, covered with few to fairly numerous, unevenly spaced, often very coarse, simple to branched, flexuous to curved excrescences 2-15 x 1-4 µm. Pleurocystidia absent. Lamellar trama dextrinoid. Hyphae of the pileipellis 2-4.5 wide, smooth to densely covered with excrescences 1.5-8 x 1-2 µm, tending to be somewhat gelatinized. Hyphae of the cortical layer of the stipe 1.5-3.5 µm wide, smooth to sparsely covered with straight to curved, cylindrical excrescences 1-7 x 1-2 µm, the terminal cells 2.5-7 µm wide, cylindrical to clavate, variously diverticulate, tending to be somewhat gelatinized. Clamp connections absent.
The macroscopic description of the species is mainly based on Maas Geesteranus (1986 b). The microscopic details are based on reexamination of two Swedish collections given to me by L. Örstadius.
This species belongs to sect. Cinerellae Singer ex Maas Geest. It can be distinguished from most of of the other species in the section on account of the 2-spored basidia and absence of clamps. M. cinerella can also be found in a 2-spored, clampless form, but can be separated by the strongly farinaceous odour when cut. In addition, the cheilocystidia of M. cinerella are differently ornamented, usually with shorter and thinner excrescences than in M. pseudopicta.
The rare species M. agrestis is somewhat similar with arcuate, decurrent lamellae, and may occur in similar habitats. It has, however, a pileus covered by a separable, gelatinous pellicle, a much larger number of lamellae reaching the stipe, and a lamellar edge separable as a gelatinous thread. Besides, the basidia are 4-spored, the spores are smaller, the pileipellis is gelatinous, and clamp connections are present in all tissues.
Robich (2003: 139) reported on a 4-spored collection of M. pseudopicta.
Microphotographs of the cheilocystidia
Microphotographs of the terminal cells
Images on the Internet:
en Catalogne nord