Macroscopic features

  Pileus 8-18 x 6-16 mm when still closed, ellipsoid, ovoid or oblong, first sulphur to citrine yellow, darker and more yellow towards the centre, becoming more yellow at maturity then isabelline towards the margin; expanded pileus 8-22 mm, distinctly umbonate, fibrillose scurfy throughout or more velvety at the disk, striate then sulcate at margin. Lamellae crowded, free, first whitish, then grey, finally violaceous black, whitish floccose at margin when young. Stipe up to 60 x 1-1.5 mm, 2-3 mm at base, hyaline or slightly brownish, equal except for slightly bulbous base which is coated with sulphur or olivaceous hyphae.

Microscopic features

  Spores [40,2,2] 9.6-11.8 x 5.3-6.8 µm, oblong, mainly rounded at apex, dark brown, with central, c. 1.6 µm wide germ pore; Q = 1.58-2.00, av. Q = 1.67-1.85; av. L = 10.3-10.9, av. B = 5.9-6.5 µm. Basidia 14-28 x 8-10 µm, 4-spored, surrounded by (3-)4-6 pseudoparaphyses. Pleurocystidia 75-175 x 25-50 µm, utriform, cylindrical or ellipsoid. Cheilocystidia 35-100 x 25-50 µm, globose to ellipsoid or broadly utriform. Elements of veil thin-walled, sometimes slightly thick-walled (< 0.5 µm) and yellowish, diverticulate, up to c. 100 x 2-10(-12) µm. Clamp-connections present.

Habitat & distribution

  On horse dung, solitary or a few together. Very rare. Not known from the Netherlands. Only known to us by the two collections cited by Watling (l.c.) and the statement by Bender (1991: 11) from Germany.

Remarks

  The macroscopical description is based on Watling (l.c.). Coprinus luteocephalus is microscopically close to C. xenobius (for differences, see the discussion under C. xenobius). In subsect. Alachuani the only other species with oblong spores is C. goudensis and that species grows on wood, the spores are distinctly smaller and the cystidia are ellipsoid or subcylindrical, never utriform.
  The status of the studied material is not clear. The envelope of Watling 7360 was empty, and the available material originates from a culture by Kemp. It seems likely that the culture was made from the holotype material, but the original description mentions another collection by Kemp (England: Cumberland, Wigton, without date), which could have been the source of the culture.
  The collection from Germany (with spores 10-11.8 x 5.3-6.3 µm; Q = 1.74-2.00, av. Q = 1.85; av. L = 10.9, av. B= 5.9 µm) has been studied but is not included in the above description because of the poor macroscopical annotation. The sizes of the spores agree with those of C. luteocephalus but are somewhat narrower. Not noted are the colour and size of the pileus. The collection was labelled C. xenobius but that species has much larger spores.
  The yellow colour and smaller spores should distinguish Coprinus luteocephalus from C. xenobius, but the Italian collections cited under C. xenobius have spores characteristic for C. luteocephalus while the basidiocarps lack the characteristic yellow tinges. This could mean that Coprinus luteocephalus may sometimes lack yellow tinges, and then only the spore-size is left to distinguish it from C. xenobius. It seems likely that one, variable taxon is involved but we need more material to confirm this.
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