Closed pileus globose, subglobose, ellipsoid or cylindrical ellipsoid, up to 5(-8) mm high and 4 mm wide, completely covered with powdery, pale pinkish brown veil (Mu. 7.5 YR 5/4, K.& W. 6C4 at centre), producing small conical flocks at centre of pileus; veil at margin, particularly in early stages, somewhat more hairy-floccose; expanded pileus up to 15(-22) mm wide, conical or convex, later flat. Lamellae, L = 16-22, l = 0-3, free, up to 1.5 mm wide, white at first, then greyish to black. Stipe up to 50 x 0.5 - 1 mm, white, somewhat hyaline. Base of stipe clavate, up to 1.5 mm wide, often brownish, with white velar flocks, often forming a small erect collar. Smell absent.
  Spores [80,3,3] 6.0-8.9 x 5.8-7.8 µm, Q = 1.00-1.35, av. Q = 1.05-1.20, av. L = 7.4-8.0, av. B = 6.6-7.0 µm, rectangular lemon-shaped, lentiform, dark red-brown, with central germ pore. Basidia 15-30 x 7-8 µm, 4-spored, surrounded by 3-6 pseudoparaphyses. Pleurocystidia 30-50 x 35-40 µm, subglobose to ellipsoid. Cheilocystidia 20-45 x 15-35 µm, globose, subglobose to ellipsoid. Pileipellis made up of (sub)globose to ellipsoid elements, smooth to granular, up to 50 µm wide. Clamp-connections absent.

Habitat & distribution

  Solitary or in small groups on compost heaps. Rather rare in the Netherlands.

Remarks

  The collections studied fit the original description very well. The original Coprinus patouillardii also growed on vegetable refuse (on dregs from decaying grapes). A macroscopically and microscopically very similar taxon from dung is described as C. cordisporus Gibbs in this paper. See the discussion under that species.
  The type material of C. patouillardii var. lipophilus Heim & Romagn. (1934: 187) proved to be very bad. It is nothing but a black mass, in which it was impossible to tell the lamellae apart. The shape and size of the spores of that material (fig. 13B) fit very well with that of C. patouillardii, however. The differences indicated by Heim & Romagnesi, viz. the larger, convex pileus, the floccose volva-like veil at base of the stipe, also fits well into the variability of C. patouillardii. The habitat, greasy soil, does not seem to be of great importance. Therefore we think it is not different from the type-variety of the species.