Pileus up to 17 x 10 mm when still closed, up to 20 mm when expanded, subglobose to oblong, densely covered with mealy to hairy floccose veil, grey to grey-brown. Lamellae free, white to black. Stipe up to 50 x 1-3 mm, whitish; base somewhat clavate. Smell none.
  Spores 8.8-12.6 x 5.2-6.7 µm, Q = 1.50-2.00, av. Q = 1.55-1.95, av. L = 9.2-11.3 µm, av. B = 5.4-5.9 µm, ellipsoid or ovoid, with conical base and rounded or somewhat truncate apex, dark red-brown; germ pore central, 1.4-1.6 µm wide; episporium strongly developed, wrinkled, up to 1.7 µm wide in places. Basidia 18-32 x 8-10 µm, 4-spored, surrounded by 3-6 pseudoparaphyses. Pleurocystidia 50-100 x 20-40 µm, utriform, oblong or subcylindric. Cheilocystidia 40-100 x 25-40 µm, (sub)globose, ellipsoid, oblong, utriform or subcylindric. Pileipellis made up hyphoid elements. Elements of veil up to 80(-100) µm wide, made up of globose, warty cells connected with narrow, diverticulate hyphae. Clamp-connections not found.

Habitat & distribution

  Rare, on moss- or algae-covered horizontal cut surfaces of trunks of coniferous and deciduous trees. Known from Great Brittain and The Netherlands.

Remarks

  Coprinus laanii can be recognised by the habitat, the narrowly spores with conical base and wrinkled episporium, and the absence of a 'narcotic' smell.