Psilocybe fimetaria

P. fimetaria is found growing solitary or in small groups on horse or cow dung, in grassy areas, in Autumn from September to November. The species is generally uncommon and infrequently recorded, but it can occasionally occur in large numbers in localized areas. Psilocybe semilanceata may be an indicator species for P. fimetaria, as they both favour similar grasses, soil types and climatic conditions.

It has been recorded in Great Britain, Iceland and much of mainland Europe. Despite what much of the literature states, there have not been confirmed recordings of P. fimetaria in Asia or the Americas (Canada, the Pacific Northwest and Chile). However, Paul Stamets suggests that the actual range in which these mushrooms fruit is likely much wider than what has been documented so far.

Psilocybe fimetaria may be visually confused with the similarly hemispherically capped species Deconica coprophila and Psilocybe liniformans or Psilocybe semilanceata as they often grow in the same habitat and share macroscopic similarities.

P. fimetaria is phylogenetically closely related to P. liniformans but can be differentiated by the latter’s separable gelatinous gill edge, which is a peelable gelatinous threads running along the bottom edge of the gills. Additionally, P. fimetaria has a distinct veil on its cap. D. coprophila can also appear similar but can be distinguished by its adnate or subdecurrent gill attachment, less dense gill spacing, and its cap being a deeper red color. Furthermore, confusion with P. semilanceata is possible, as P. fimetaria can sometimes be conic-shaped, though generally not as sharply conical as the distinctive shape of P. semilanceata. Additionally, P. semilanceata prefers cow and sheep pastures but does not directly grow on dung, unlike P. fimetaria.