Macroscopic features

  Pileus up to 12 x 9 mm when still closed, ochre-brown to cinnamon-brown (Mu. 10 YR 5/6 to 6/8, K. & W. 5C5 to 5A6, 5B5), up to 25 mm in diam. when expanded. Lamellae narrowly adnate, up to 2 mm broad; L= c. 32, l= 1-3, white to blackish. Stipe 40-80 x 1-3 mm, whitish, pubescent.

Microscopic features

  Spores [80,4,3] 10.3-13.7 x 6.3-8.3 µm, av. L= 11.4-12.2, av. B= 7.0-7.9 µm, Q= 1.45-1.70, av. Q= 1.55-1.60, ellipsoid to ovoid; germ pore eccentric, c. 1.8 µm wide. Basidia 16-32 x 7-9 µm, 2-spored. Pseudoparaphyses 4-6 per basidium. Cheilocystidia 25-55 x 20-35 µm, globose to ellipsoid. Pleurocystidia 40-65 x 28-37 µm, subglobose to ellipsoid. Pileocystidia 50-110 x 12-25 µm, lageniform with tapering neck, 5-8 µm wide at apex. Sclerocystidia absent. Clamp-connections absent.

Habitat

  Growing in woods, among leaves and on fallen branches. Rare.

Remarks

  Coprinus bisporiger is very similar to C. bisporus but grows on fallen branches and among leaves, whereas C. bisporus is fimicolous. Orton & Watling (1979: 88) suggest that C. bisporiger also differs in the presence of thick-walled setulae. Bender (1987: 219) stated that C. bisporiger has pleurocystidia. The first author of this paper indeed found these in Bender's collection cited above, but only in the half of the lamellae closest to the edge. In the Netherlands' collection pleurocystidia were lacking. The first author was only able to find spores and pileocystidia in Buller's type collection of C. bisporiger.