Psilocybe castanella Peck, Bull. N. Y. State Museum 1: 7. 1887.

macroscopy:

Pileus 5-15(-25) mm, conical, hemispherical to convex when young, expanding to convex, plano-convex or applanate, sometimes concave, but usually with small, blunt umbo, with deflexed then straight margin, which sometimes exceeds the lamellae, marginal zone sometimes grooved, weakly to strongly hygrophanous, when moist not or shortly translucently striate at margin only, reddish brown (Mu. 5 YR (3/2)3/3-4/3-4/4) pallescent to yellow-red (5 YR 5-6/8; K&W 9F8, 8F4, margin 7.5 YR 6/2-4; 7F7-8, 7E5), entirely covered with fine velar patches, glabrescent at centre, margin long with fibrillose velar patches, sometimes appendiculate, in fresh specimens surface appearing dusted with a dull greyish covering on red-brown background, absolutely dry, without peeling pellicle. Lamellae , L = 20-30, l = 1-3(-5), moderately distant to fairly crowded, broadly adnate with decurrent tooth to deeply decurrent on stipe, brown, long remaining so, finally with purple-brown tinges from ripe spores (7.5-5 YR 5/6-4/4 then 5 YR 3/3-4; 7D6-7), with irregular to fimbriate, subconcolorous or paler edge. Stipe 15-50 x 1-2(-2.5) mm, cylindrical with slightly to distinctly swollen base or tapering towards base, straight or flexuous, yellow-brown at apex, darker red-brown towards base (7.5 YR 3/2 to 5 YR 3-4/4-2; 6C5-6-6B4, base 7F7-8), entirely finely fibrillose-pruinose to minutely flocculose, sometimes with narrow annuliform zone, basal part with white to grey tomentum. Context concolorous or slightly paler than surface in pileus, colouring darker purplish brown with age. Smell spontaneously weak or slightly farinaceous. Taste indistinct. Spore print very dark red-brown (10 R 2.5-3/2, 5 YR 3/3).

microscopy:

pores 6.5-8.0(-8.5) x 4.0-5.5(-6.0) x 4.0-5.5(-6.0) µm, not or slightly flattened, F/I less than 25 %, Qf = 1.3-(1.4-1.5)-1.7, broadly ellipsoid to ovoid in frontal view, Qs = (1.3-)1.4-(1.5-1.7)-1.8, ellipsoid to oblong or slightly amygdaliform in side-view, with thin to slightly thickened wall, with small, but distinct apical germ-pore, pale brown to greyish in NH3. Basidia 4-spored, clamped. Lamella edge sterile. Cheilocystidia 21-36 x 4.0-8.0, narrowly lageniform to clavate with blunt, rounded tot subcapitate, 1.5-3.5 µm wide apex. Pleurocystidia absent. Hymenophoral trama regular, made up of short, cylindrical to inflated elements, 10-40 x 5.0-8.0 µm, mixed with 2.0-5.0 µm wide, cylindrical connective hyphae, with yellow, often minutely incrusted walls. Pileipellis a narrow cutis of cylindrical hyphae, 3.0-7.0 wide with hyaline to finely encrusted walls; subpellis compact, made up of short inflated elements, 7.0-35(-55) x 5.0-15(-17) µm with red-brown, strongly incrusted walls, gradually passing into pileitrama. Pileitrama regular to irregular, made up inflated elements, 12-90(-100) x 2.0-7.0 µm with hyaline, rarely incrusted walls. Clamp-connections present.

ecology:

in meadows, usually attached to the base of grasses or on dead grasses.

distribution:

Besides the type-locality in the U.S.A. it is known from the United Kingdom and France.

comment:

P. castanella has been described from Europe under the name P. apelliculosa Orton. Type studies have shown that both are conspecific