Pileus 4-7(-10) x 2-5(-7) mm when still closed, 8-14(-18) mm wide when expanded, at first campanulate to hemispherical, conical campanulate with rounded apex to convex when expanding, finally flat, sulcate-striate up to centre, red-brown (Mu. 5YR 3/4) at centre and on ridges, later somewhat paler (from 7.5 YR 4/6 to 5/6), near margin pale grey-brown (10 YR 5/3), margin whitish, finally turning grey from margin towards centre, glabrous. Lamellae free, L = 16-24, l = 0-1(-3), fairly distant, up to 2 mm wide, at first whitish, later grey-brown to almost black. Stipe up to 70 x 0.6-1.2 mm, slightly thickening towards subbulbous, up to 1.5 mm wide base, whitish, somewhat vitreous, glabrous, very fragile. Spore print blackish with faint purplish hue.
  Spores 12.4-17.2 x 11.3-15.2 x 8.2-10.8 µm, Q = 1.05-1.30, av. Q = 1.05-1.20, av. L = 13.6-15.7 µm, av. B = 11.8-13.3 µm, rounded triangular to weakly 5- or even 7-angular, lentiform, with strongly eccentric germ pore; with convex base and rounded apex, very dark red-brown to almost black. Basidia 22-51 x 13-16 µm, 4-spored surrounded by 5-8 pseudoparaphyses. Pleurocystidia 60-105 x 22-30 µm, subcylindrical to (sub)utriform. Cheilocystidia 45-70 x 10-23(-30) µm, from clavate or vesiculose with short broad neck to broadly utriform or broadly cylindrical. Pileipelllis a hymeniderm of clavate to spheropedunculate cells 50-70(-100) µm long and up to 23 µm wide. Clamp-connections present.

Habitat & distribution

  On open, regularly mown lawns on clayey soil of recreation areas. Solitary or a few together, in small groups. Not common but probably overlooked. Known only from five localities in the Netherlands. Also recorded from Germany.

Remarks

  Differs from Coprinus schroeteri in having smaller basidiocarps, broader spores and the lamellae more distant. Coprinus miser P. Karst. has smaller basidiocarps, much smaller spores and the habitat on dung.