Pileus 10 x 7 mm when still closed, up to 20 mm when expanded, first ellipsoid or ovoid, then obtusely conical to convex, pale brown, darker in centre. Veil ochre with distinct green tinge, around centre breaking up in small, floccose scales. Lamellae rather crowded, free, first white, then grey-brown, finally black. Stipe up to 40 x 1-2 mm, whitish; base slightly clavate.
  Spores [60,3,1] 11.9-15.3 x 7.7-10.5 µm, amygdaliform, smooth, truncate, dark red-brown, with central, c. 2.5 µm wide germ pore; Q = 1.30-1.60, av. Q = 1.45-1.50; av. L = 12.7-13.8, av. B = 8.4-9.4 µm. Basidia 15-32 x 9-12 µm, 2-spored, surrounded by 4-6 pseudoparaphyses. Pleurocystidia 55-90 x 22-40 µm, subglobose, ellipsoid or utriform. Cheilocystidia 40-85 x 25-45 µm, (sub)globose, ellipsoid, sometimes oblong. Elements of veil thin-walled, diverticulate, 3-9(-12) µm thick, rather strongly incrusted. Clamp-connections present.

Habitat & distribution

  In small groups on burned places, a few together. Very rare, only known from type-locality.

Remarks

  Microscopically Coprinus piepenbroekii is easily recognized by the smooth, large, amygdaloid spores and the 2-spored basidia. The greenish tinge of the fresh basidiocarps is characteristic for this species.