Pileus 5-30 x 3-18 mm when still closed, 10-60 mm wide when expanded, first ellipsoid or ovoid, often somewhat conical, then campanulate to convex, finally flat, sulcate-striate up to centre, chestnut-colour, red-brown or orange-brown (Mu. 2.5 YR 2.5/2, 3/?, 2.5/4, 3/4; 5 YR 2.5/2, 3/3, 3/4, 4/4, 4/6, 4,5/7.5; 7,5 YR 5.5/4, 4/6, 5/8; 10 YR 4/6, 5/6; K. & W. 7FG) at centre, paler towards margin, glabrous, but very fine pruinose from sclerocystidia when young and fresh. Lamellae, L = 30-40, l = 0-3, free but not remote from apex of stipe, first whitish, then brown (Mu. 5 YR 2.5/1, 3/1, 3/3), finally black. Stipe 70-120 x 2-3 mm, with subbulbous base, sordidly white to sordidly yellow-brown (Mu, 10 YR 8/ 1).
  Spores 10-14.3 x 5.8-8.2 µm, Q = 1.35-2.05, av. Q = 1.45-1.95, av. L = 10.8-13.1 µm, av. B = 6.8-7.5 µm, ellipsoid to oblong, with central to (rarely) slightly eccentric germ pore and rounded at base and apex, dark red-brown. Basidia 4-spored, surrounded by 3-6 pseudoparaphyses. Pleurocystidia 70-140 x 22-45 µm, subcylindric or utriform. Cheilocystidia 50-95 x 17-25 µm, utriform, sublageniform, subcylindric or ellipsoid. Pileipellis hymeniform, with scattered long, brown, thick-walled hairs (sclerocystidia). Base of stipe also (densely) set with sclerocystidia. Clamp-connections present.

Habitat & distribution

  Terrestrial at grassy places, road-sides, etc., but also locally very abundant on woodchips used to pave paths and tracks. Subfasciculate, a few together or - less frequent - solitary in small groups. Rather common in spring and summer, rather rare in autumn. Wide-spread in Europe. Recorded from Japan.

Remarks

  Microscopically Coprinus auricomus can be easely recognized by the smooth stipe (no veil, no caulocystidia), the hymeniform pileipellis with the scattered thick-walled, brown setae and the ellipsoid spores with central germ pore.