Pileus up to 20 x 15 mm when still closed, up to 30 mm when expanded, subglobose to oblong, densely covered with mealy to hairy floccose veil, mouse grey. Lamellae, L = c. 40, l = 0-3 free, white to black. Stipe 60(-80) x 1-5 mm, whitish; base somewhat clavate. Smell somewhat of yeast or none.
  Spores 11.6-15.8 x 7.6-8.4 µm, Q = 1.50-1.90, av. Q = 1.70-1.75, av. L = 13.9-14.9 µm, av. B = 8.1-8.7 µm, ellipsoid or ovoid, with rounded base and apex, dark red-brown; germ pore central, 1.5-1.8 µm wide; episporium smooth, up to 1.3 µm wide in places. Basidia 16-38 x 8-12 µm, 2-spored, surrounded by 3-6 pseudoparaphyses. Pleurocystidia 60-100 x 30-45 µm, utriform, oblong or subcylindric. Cheilocystidia 40-90 x 30-50 µm, (sub)globose, ellipsoid, oblong, utriform or subcylindric. Pileipellis made up hyphoid elements. Elements of veil up to 80 µm wide, made up of globose, warty cells connected with narrow, diverticulate hyphae. Clamp-connections not distinct, if present very sparse, probably only pseudo clamps.

Habitat & distribution

  Very rare, terrestrial among grasses. Known from England and The Netherlands.

Remarks

  The spores with rounded base and apex distinguish Coprinus saccharomyces from the close related and also 2-spored species C. cinereofloccosus, which have narrower spores with conical base.