Psilocybe fimetaria, known as the “fringed” psilocybe, is a rare but widespread specie. It gains its name from the latin word for fringe, “fim-”, this mushroom’s main feature. Along with the characteristic cap, it is commonly found on or near dung, a “coprophilous” nature that is relatively rare among Psilocybe. Despite their “diet”, they have a mild and starchy scent and flavour.
This specific preference has led to its nearly worldwide distribution; it is found on or near horse or elephant dung on nearly all continents. It may be found solitary or in small groups, rarely they can be found fruiting in large rings. P. fimetaria is believed to have originated in Europe, found primarily on the British Isles. It has since spread to North America (Pacific Northwest, New Brunswick), South America (Chile), and Asia (India).
Due to its disparate appearances, it has been misidentified or recategorized over the years since its initial discovery. P. fimetaria has been known as both Psilocybe caesieannulate and Stropharia fimetaria. Regardless of the name, the species has always been known to contain alkaloids: Psilocybin has been confirmed, Psilocin is suspected.
These active compounds contribute to the ready bluing reaction of P. fimetaria after handling or with age. It also commonly has blue spots or hues near the base of the stipe. The slender stem, up to 9 centimetres, is usually covered with fine, whitish fibrils or hairs; it features a ring, or “annulus”, left by a veil, or “cortina”, between the edge of the cap and the stipe.
The cap itself is variable with a shape that varies from convex, flat, to bell-shaped, sometimes with a sharp papilla or broad umbo. The colour might vary by region: reddish-brown, ochre, honey, even greenish-yellow have all been described. When wet, the cap is sticky or slippery due to a gelatinous pellicle; this also gives the edges translucent striations.
While this species is a rare find in the wild, its wide range opens the possibility to many areas of the globe. While having few distinct features, the combination makes this mushroom reliably identifiable. With the potency unknown, consumption should be with caution.
Guzmán, Gastón. “Species diversity in the genus Psilocybe (Basidiomycotina, Agaricales, Strophariaceae) of world mycobiota, with special attention to hallucinogenic properties.” International Journal of Medicinal Mushrooms 7.1/2 (2005): 305.