Psathyrella spadicea (Schaeff.) Singer

Diagnosis fuente: PERSOONIA - Suplement - Vol. 2 - THE DUTCH, FRENCH AND BRITISH SPECIES OF PSATHYRELLA – 1985 E. KITS VAN WAVEREN - Rijksherbarium, Leiden, The Nederlands
     Cap 20-100 mm broad, in early stages paraboloid, then conico-paraboloid with incurved margin, soon spreading to convex with deflexed marginal area, finally plane, often with revolute and/or flexuous marginal area, sometimes vaguely umbonate or with depressed centre, fleshy, firm, at first very dark reddish brown (Mu. 2.5 YR 3/2, 2.5/4), at maturity dark reddish incarnate-brown (Mu. 5 YR 4/3, 3/3, 4/4, 4/3), slightly paler near margin (Mu. 5 YR 5/2, 5/3, 5/4), not striate or only substriate at margin over 2-5 mm, with greasy, smooth, hygrophanous surface, drying out from centre to sordid greyish yellow (Mu. 7.5 YR7/4; 10 YR 6/4, 7/3, 7/4, 8/3) sometimes with pinkish hue, pale ochre at centre, not micaceous or rugulose. Veil absent. Gills 4-10 mm broad, crowded, + horizontal but strongly rounded close to stem and then narrowly adnate (rarely broadly), at first brown (Mu. 7.5 YR 5/4), at maturity brown-incarnate, brown-chocolate, reddish brown (Mu. 5 YR (Mu. 7.5 YR 5/4), at maturity brown-incarnate, brown-chocolate, reddish brown (Mu. 5 YR4/4, 3/4, 5/3, 5/4) or warm brown (Mu. 7.5 YR 5/4), with white or concolorous fimbriate edge. Stem 20—70 x 3—4 mm, but when springing from cavity of hollow tree stump up to80-140 x 10-15 mm, cylindrical, often flexuous, at extreme base often attenuated, hollow, white, whitish, isabelline or very pale brown, distinctly and sometimes even coarsely fibrillose striate to (in upper part) subsulcate. Flesh of cap concolorous, 3—5(—7) mm thick in centre, in stem fibrous, whitish to pale brown. Trama of ‘washed’ gill rather strongly pigmented, brownish yellow; pale brown (Mu. 10 YR 7/3), darker from edge to base (via Mu. 10 YR 6/3 to 5/3), but mixed with brownish yellow (Mu. 10 YR 6/6) from numerous, anastomosing strands running from base to edge. Spore print reddish chocolate Brown.
     Spores 7-10 x 4—-5.5 ym (mean values 8—9.1 x 4.2—5 um: 9 collections), in face view ellipsoid or ellipsoid-ovoid, in profile ellipsoid but many spores distinctly phaseoliform, conspicuously pale, in water pale yellowish pink (Mu. 7.5 YR 7/4, 8/4, 8/6, in NH,OH 10% pale brown (Mu. 7.5 YR 6/4), in KOH 5% very pale sordid brown, not opaque; germ pore absent; hilar appendix distinct. Basidia 20-30 x 6.5—9.5 um, clavate, 4-spored. Pleurocystidia35—65(—70) x 12.5—22.5(-25) um, numerous, near edge abundant, ventricose-fusoid with short or somewhat longer pedicel and gradually tapering towards acute or subacute (subobtuse) apex, with wall + 0.5 um thick, almost always thickening in upper + 1/3 of cell or with a local thickening just below apex, at very apex 1.5~3(—4) pm thick, practically colourless or very pale brown in NH,OH 10%; thick-walled upper part strongly colouring red in Congo Red. Apex of cells usually covered with a granular crystalline substance or conspicuous crystals, both dissolving in KOH, not in NH,OH 10%. Marginal cells: pleurocystidioid cheilocystidia 35—75 x 15-25 um, abundant and densely packed, sizes and shapes very variable, intermixed with few to sometimes moderately numerous, usually large, spheropedunculate and clavate, rarely utriform, thin-walled cells, 17.5—47.5 x 10-27.5 um and transitions between pleurocystidioid cheilocystidia and spheropedunculate cells. Hymenophoral trama in NH,OH 10% sub micr. distinctly yellowish brown from membranal pigment, particularly the subhymenium in which however few yellow hyphal septa, no encrustations present. Pileipellis a 2—4 cells deep layer of versiform, subglobose and oblong colourless cells 15—30 pm diam.
HABITAT & DISTRIBUTION. — Caespitose, rarely solitary, on treestumps, usually of Fagus, also found at foot of live trees (Castanea, Betula).