Psathyrella leucotephra (Berk. & Broome) P.D. Orton

Diagnosis Fuente: PERSOONIA - Suplement - Vol. 2 - THE DUTCH, FRENCH AND BRITISH SPECIES OF PSATHYRELLA - 1985 E. KITS VAN WAVEREN - Rijksherbarium, Leiden, The Nederlands
     Cap in earliest stages 10-25 mm, subglobose, with strongly incurved margin, a aisunct velar membrane connecting margin with stem, pale brown, buff (Mu. 10 YR 7/4, 6/4), smooth, in later and mature stages, (20—)30-70(—80), semiglobose to paraboloid, with margin still incurved, becoming paler, very pale brown, cream-coloured, alutaceous or sordid whitish with slightly darker, pale ochreous or yellowish brown centre (Mu. + 7.5 YR6/6), finely radially rugulose, finally spreading to convex or plano-convex with vague, but sometimes distinct and large unbo, not striate, hygrophanous, drying out to whitish (Mu. 10 YR 8/2) with centre sordid ochreous-yellow (Mu. 10 YR 8/3, 8/4), without pink, not micaceous. Veil forming on surface of cap near margin fugacious arachnoid fibrils, isolated or in small bundles (in places sometimes even squamules), furthermore either appendiculate white denticles at margin or a conspicuous, up to 7 mm broad, pendulous, usually adpressed but sometimes spreading, often torn annulus (cuff) at about 1/3-1/4 of length of stem from apex, its upper surface striate-sulcate, its under surface arachnoid-felty; remnants of veil at maturity often scarce or even absent. Gills 2.5—-S5 mm broad, crowded, at first very pale brown (Mu. 10 YR 7/3), soon pale greyish, finally dark brownish grey to predominantly grey with a trace of purple (Mu. 7.5 YR 5/2), at first concave near margin and ventricose near stem, later + straight, ascending, narrowly adnexed, with white fimbriate edge. Stem70-160 x S—8-12 mm, cylindrical, white, hollow, striate above and smooth, silky below insertion of veil (annulus), springing with many other stems from a common very pale yellowish brown, fibrous-flocculose base. Flesh of cap in centre 1.5—4 mm thick, pale brown (Mu. 10 YR 6/3, 5/4), towards margin very pale brown. Smell and taste indistinctive. Trama of ‘washed’ gill in NH,OH 10% under binocular lens very pale brown only near base, gradually even paler towards edge. Spore print black.
     Spores (7—)8—10 x 5—6 um (mean values 8.4—9.2 x 5.2—5.4 um: 5 collections), in face view ovate but with rectangular base, in profile often slightly phaseoliform, very dark, in water dark reddish brown (Mu. 10 R 3/4), in NH,OH 10% darker (Mu. 2.5 YR 3/2), in KOH 5% dark brown (Mu. 7.5 YR 3/2), not opaque, without germ pore, with small hilar appendix. Basidia 21-29 x 9.5—11 um, clavate, 4-spored. Pleurocystidia absent. Marginal cells: utriform cheilocystidia rather small, 25-40 x 7.5-12.5 to 6-8 ym, abundant and densely packed, without accompanying spheropedunculate cells, thin-walled, colourless. Hymenophoral trama in NH,OH 10% sub micr. practically colourless to very pale brown, without yellow hyphal septa or encrustations. Pileipellis a 3—4 cells deep layer of colourless cells, 25—40 um diam.
HABITAT & DISTRIBUTION. — Caespitose in large clusters (10-30 specimens) in clayey soil around stumps of deciduous trees, Aug.-Oct. Rare in the Netherlands. Reported from France and the British Isles.