Psathyrella pseudogordonii Kits van Wav.

Diagnosis fuente:  PERSOONIA - Suplement - Vol. 2 - THE DUTCH, FRENCH AND BRITISH SPECIES OF PSATHYRELLA - 1985 E. KITS VAN WAVEREN - Rijksherbarium, Leiden, The Nederlands
Cap 20—45 mm, paraboloid, expanding to convex, sometimes slightly umbonate, livid grey or horn colour, often tinged sepia or date brown at centre, striate at margin, hygrophanous, drying out to whitish with pale ochraceous or sordid-brownish centre while becoming matt or with slight silky sheen. Veil white, in early stages forming scattered silky fibrillose patches on entire cap, copiously appendiculate at margin, later leaving cap with smooth centre and rather thick dentate scales or patches at or near margin, on stem floccose-scaly; flocci becoming larger and denser towards base, sometimes leaving ringlike traces about half-way down. Gills rather crowded, adnate, often rather narrow, lanceolate, not or slightly ventricose, greyish or with slight violaceous tinge, finally pallid umber, with white flocculose edge. Stem 35-70(-110) x 2-6(-8) mm, attenuated upwards, flexuose, pure white, then discolouring pale dirty brownish below, silky striate, hollow, fragile, with white pruinose-floccose apex and white tomentose base. Flesh concolorous in cap, horny over gills, white in stem, discolouring pale dirty ochraceous in lower stem. Trama of ‘washed’ gill very pale brown (Mu. 10 YR 7/3) from base to edge. Spore print violaceous umber.
Spores 8—11 x 5—6.5 pm (mean values 9.4.x 5.5 um: 1 collection), size variable, ellipsoid or ellipsoid-ovoid, adaxially flattened, in water and NH,;OH 10% warm brown (Mu. 5 YR 4/6, 4/8), in KOH 5% sordid brown (Mu. 10 YR 5/3), not opaque, with small germ pore (1.5 pm) and distinct hilar appendix. Basidia 19~22.5 x 9-9.5 ym, clavate, 4-spored. Pleurocystidia absent. Marginal cells: cheilocystidia 20-35 x 9-11 ym, utriform (sublageniform), with thick neck and sometimes subapical constriction, abundant and densely packed, intermixed with some basidia and many inconspicuous, small, spheropedunculate cells, 10—12.5 x 5—7.5 um; all cells thin-walled, colourless. Hymenophoral trama in NH,OH 10% sub micr. very pale brown, without yellow septa or encrustations. Pileipellis a 2—4 cells deep layer of subglobose colourless cells, 15—30 ym diam.
HABITAT & DISTRIBUTION. — Densely caespitose or gregarious on stumps of Fagus.