Closed pileus up to 13 x 10 mm, yellow-brown to date-brown, more frequent dark red-brown at centre (Mu. 2.5 - 5 YR 2.5/2, 7.5 YR 3/3 to 6/6, K. & W. 5E7 to 5D8), paler towards margin (5 YR 4/3), up to 25 mm in diam. when expanded. Granular-flocculose veil present on pileus. Lamellae free to narrowly adnate, white in very young stage, blackish at mature. Stipe 40-80 x 1-2 mm, whitish, pubescent.
  Spores [60,3,3] 9.7-14.3 x 6.3-8.7 x 6.2-7.3 µm, av. L= 10.7-12 µm, av. B= 7.4-7.7 µm, Q= 1.30-1.70, av. Q= 1.45-1.55, hexagonal in front view; germ pore eccentric, c. 1.8 µm wide. Basidia 16-38 x 9-12 µm, 4-spored. Pseudoparaphyses (3-) 4-5 (-6) per basidium. Cheilocystidia 20-70 x 17-40 µm, ellipsoid to globose. Pleurocystidia 60-90 x 20-35 µm, oblong, ellipsoid to subglobose. Sclerocystidia absent. Velar spherocysts on pileipellis up to c. 40 µm in diam., globose. Pileocystidia 50-100 x 12-20 µm, lageniform with cylindrical, 6-10 µm wide neck and equal to slightly broader, up to 12 µm wide apex. Clamp-connections present.

Habitat

  On dung, mixtures of straw and dung and decaying grass. Subgregarious. Rather rare.

Remarks

  This species is easy to recognize by its six-angled spores. In the literature, it is usually named C. hexagonosporus Josserand. Enderle & al. (1986: 118), however, discovered that C. marculentus Britz. is identical with C. hexagonosporus. The description of Britzelmayr and in particular his drawings leave no doubt about the synonymy of these two names, of which C. marculentus is the oldest and has to be used for this species. Josserand also described C. hexagonosporus var. stephanosporus (1948: 86) and Malen‡on (1970: 241) C. hexagonosporus Joss. var. homosetulosus. Enderle & al. (l.c.) introduced new combinations for both of these variants.
  According to Josserand his variety was distinguished by the presence of small warts around the suprahilar plage, pronounced in NH4OH or HCl. Enderle & al. attached little value to this character and reduced Josserand's variety to forma, C. marculentus f. stephanosporus (Joss.) Enderle.
  Coprinus marculentus Britz. var. homosetulosus (Malenç.) Enderle would be recognizable by the probable absence of pleurocystidia and lageniform cheilocystidia.