Psilocybe xeroderma Huijsman, Persoonia 2: 94. 1961.

macroscopy:

Pileus 5-20 mm, convex, plano-convex or very obtusely conical, hygrophanous, translucently striate at margin, reddish brown or chocolate-brown (K. & W. 8F6, 7D-E8), pallescent from centre to yellow-brown or ochraceous, dry to slightly viscid, but without separable pellicle, covered with white, silky fibrillose, fugacious remnants of veil, sometimes appendiculate; lamellae, L = 22-30, l = 3, moderately crowded, adnate-arcuate to subdecurrent, brown then purple-brown, with paler, irregular crenulate-denticulate edge; stipe 15-40 x 1-2 mm, subflexuous, stuffed or fistulous, subequal, sometimes somewhat tomentose at base, slightly flocculose-pruinose at apex, with fugacious remnants of veil, pale pinkish brown at apex, much darker towards base, which becomes very dark brown with age. (6C-D6, 6E7); context rather thick and pale in the pileus, subconcolorous in the stipe; spore print purple-black.

microscopy:

Spores 5.5-7.0 x 4.0-5.0(-5.5) x 3.5-4.5 µm, ovoid to slightly mitriform in frontal view, Q = 1.25-1.5, Qav = 1.3-1.4, ellipsoid to oblong, sometimes slightly amygdaliform in side-view, Q = 1.25-1.7, Qav = 1.4, with sordid brown, distinctly thickened walls, with small to fairly large, apical germ pore; basidia 16-27 x 5.0-7.5, 4-spored; lamella edge sterile; cheilocystidia 19-30(-33) x 4.5-11.5 µm, broadly to narrowly lageniform with 2.0-8.0 wide, blunt neck, thin-walled, colourless; pileipellis a narrow cutis of hyaline, colourless, cylindrical, 1.0-3.5 µm wide hyphae, subpellis compact, made up of cylindrical to inflated elements, 10-55(-70) x 2.5-14 µm, gradually passing into pileitrama; pigment yellow-brown, membranal and incrusting in subpellis and upper pileitrama; stipitipellis a cutis of narrow, cylindrical, 1.5-4 µm wide, yellow-brown, minutely incrusted hyphae; caulocystidia few, at apex of stipe only, single or in clusters, cylindrical to clavate or sublageniform, 10-23 x 2.0-7.0 µm,; clamp-connections present in all tissues studied.

ecology:

Saprotrophic, in small groups in raw humus in mountainous, or subalpine habitats, under or near conifers (Pinus sylvestris, P. mugo). June-Sept.

distribution:

So far recorded from Austria, France and Switzerland.

comment:

Psilocybe xeroderma clearly belongs to the complex of Psilocybe montana, from which it can be differentiated by its smaller spores and rather short cheilocystidia, usually with broad basal part and blunt, rounded neck. P. alpestris Sing. is a synonym.