Closed pileus subglobose, ellipsoid, cylindrical ellipsoid or ovoid, up to 5(-7) mm high and 3 mm wide, completely covered with powdery, pale pinkish brown or yellowish veil, forming small conical flocks at centre of pileus; expanded pileus up to 10(-13) mm wide, conical or convex, later applanate. Lamellae, L = 14-23, l = 0-3, free, white at first, then greyish to black. Stipe up to 50 x 0.5-1 mm, white, somewhat hyaline; at base clavate, up to 1.5 mm wide, with yellowish or pale brown velar flocks, forming a small erect collar when very young, later forming the ring about halfway the stipe or lower. Smell absent.
  Spores [60,3,3] 5.8-9.2 x 5.4-8.0 x 4.4-4.9 µm, Q = 0.95-1.20, av. Q = 1.05-1.15, av. L = 6.7-8.6, av. B = 6.3-7.6 µm, rectangular lemon-shaped, lentiform, dark red-brown, with central germ pore. Basidia 13-28 x 7-9 µm, 4-spored, surrounded by (3-)4-7(-8) pseudoparaphyses. Pleurocystidia 30-60 x 20-35 µm, vesiculose, utriform, ellipsoid, cylindrical ellipsoid. Cheilocystidia 20-60 x 15-35 µm, utriform, vesiculose, (sub)globose or ellipsoid. Veil 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 dung, especially from horse. Rather common in the Netherlands.

Remarks

  Coprinus ephemeroides is a species close to C. patouillardii and C. cordisporus. It differs by having a small annulus and by the colour of the pileus which usually is more yellowish.
  The sparse lageniform cheilocystidia, similar to those found in Coprinus cordisporus were also noted in C. ephemeroides (coll. C.B. Uljé 1182).
  Orton & Watling (1979: 68) mentioned a somewhat similar 2-spored taxon. On account of the larger spores and the larger and greyer fruitbodies they think the difference warrants separation as a distinct species.