Pileus 8-45 mm, conical to conico-convex with involute margin, expanding to conico-convex or plano-convex with or without low umbo, with deflexed margin, hygrophanous, viscid when moist, not translucently striate, shining when dry, yellow to yellow-brown (Mu. 2.5 Y 8/6) when young, then yellow-brown at centre (2.5 Y 5/6 or 10 YR 8/6) paler yellow towards margin (2.5 Y 8-7/4) at margin almost white, pallescent on drying to very pale brown (10 YR 8-7/4); marginal zone covered with appressed whitish-ochraceous velar patches; margin sometimes appendiculate with fine whitish velar flocks. Lamellae, L = 20-30, l = 3-5, (moderately) distant, adnate, sometimes with short decurrent tooth, segmentiform, 3-7.5 mm broad, greyish when young then purple-brown (10 YR 6/1 then 5 YR 3-4/3-1) with white, fimbriate edge.
Stipe 55-110 x 3-5 mm, cylindrical or flexuous, fistulose, very pale yellow, becoming brownish towards base, with faint to more or less distinct fibrillose annuliform zone near apex, minutely pruinose at apex, woolly-fibrillose to subsquamulose in lower part. Context concolorous with surface in cortex, white in inner parts. Smell and taste indistinct.
microscopy:
Spores 12-18.5 x 7.5-10 x 7.5-10 µm, Q = 1.5-2.1, Qav = 1.7-1.9 in side- and frontal view, oblong, rarely slightly hexagonal in frontal view, ellipsoid to oblong in side-view, with rather thick, brown wall and large germ pore. Basidia 20-39 x 6.0-9.0(-12) µm, 4-spored, clamped. Lamella edge sterile. Cheilocystidia 34-48 x 3.0-9.0 µm, subcylindrical to narrowly clavate with rounded to subcapitate apex. Pleurocystidia absent. Pileipellis an up to 100 µm thick ixocutis of narrowly cylindrical, 2.0-6.0 µm wide hyphae. Pigment membranal and incrusting in upper pileitrama. Stipitipellis a cutis of cylindrical, 3.0-9.0 µm wide hyphae. Caulocystidia 15-29 x 3.0-8.0 µm, abundant at apex of stipe, subcylindrical to irregularly clavate. Clamp-connections present.
ecology:
Saprotrophic, gregarious on dung of herbivores (cow, horse) in grasslands on sandy soil. June-Oct.
distribution:
Europe, real distribution badly known, rarely recorded, but probably overlooked.
comment:
According to Guzmán (Psilocybe: 221-223. 1983 ) Ps. merdicola is a synonym of Ps. argentina (Speg.) Sing., which has a wide distribution in the Americas. Psilocybe merdaria,Ps. moelleri and Ps. coprophila differ by their slightly to distinctly hexagonal spores in frontal view.
