Hoed 8-45 mm,
hygrofaan, geel tot geelbruin, niet doorschijnend gestreept, kleverig, met fijnevezelige velumresten en soms ook vlokjes aan de rand. Plaatjes donker roodbruin bij rijpheid. Steel 55-110 x 3-5 mm, bleek geel, later bruin wordend, fijn gestreept vezelig met een vezelige ringzone. sporen 12-18.5 x 7.5-10 x 7.5-10 µm afgeplat, verlengd eivormig zelden iets hoekig in vooraanzicht met dikke wand en grote kiempore.
In groepjesop mest van herbivoren in graslanden op zandgrond, Heel zeldzaam.
Het keutelkaalkopje onderscheidt zich van de andere twee bleekgele mestkaalkopjes voornamelijk door de vezelige ring en nauwelijks hoekige sporen.
uitgebreide Engelse beschrijving:
macroscopy:
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.
