|Gills on hymenium
|Cap is convex or umbonate
|Hymenium is adnexed or free
|Stipe has a cortina
|Spore print is blackish-brown to purple
|Ecology is saprotrophic
|Edibility is psychoactive
Psilocybe fimetaria is a psilocybin mushroom, having psilocybin and psilocin as main active compounds. It grows exclusively on horse and cow dung.
P. fimetaria is found growing solitary to gregariously on horse or cow dung, in grassy areas, from September to November. Psilocybe semilanceata may be an indicator species for P. fimetaria, as they favour similar grasses, soil types and climatic conditions. It is widely distributed but not very common.
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.
P. fimetaria is phylogenetically a close relative of Psilocybe liniformans. Not only do they often grow in the same habitat, but they are macroscopically similar. The best way to differentiate the species by testing for the presence of separable gelatinous threads running along the bottom edge of the gills. This feature would indicate P. liniformans.
Deconica 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 colour.