Psilocybe strictipes has a long, confusing and convoluted history of categorization and identification. It was originally known as P. callosa, or sometimes placed as a sub-species to the related P. semilanceata. After erroneously being described as P. baeocystis, a distant relative, in scientific literature and most guidebooks, the amateur mycologist Paul Stamets resolved the confusion in his seminal 1996 book (Psilocybin Mushrooms of the World) and cemented the title of P. strictipes.
The name itself is a latin translation of “narrow foot”, a reference to the mushroom’s slender stipe. While thin, it can grow to a height of 10 centimetres, usually dependent on the length of the surrounding grass in which it is normally found. This preference places P. strictipes in grassy meadows and lawns, though never directly on dung, throughout much of the Northern Hemisphere.
The wide range of P. strictipes is likely due to its close association with commercial grass seed production in the United States. The spore-coated seeds are shipped around the world, allowing new colonies to be established in far-flung countries. While the natural range of P. strictipes was originally thought to be temperate or subarctic regions of the Northern Hemisphere, they have been discovered as far south as Chile.
The vast majority of these mushrooms are scattered across cooler regions of Europe: as far west as the UK, as far north as Sweden, as far south as Italy and as far east as Siberia and Slovakia. They fruit in these regions when the weather shifts towards winter, usually in late summer or early autumn, though are still relatively rare. In this area, it is frequently confused with the more common P. semilanceata, or “Liberty Cap”. P. strictipes can be differentiated by a lack of papilla and a slightly different overall cap shape.
The cap ranges from conic to bell-shaped and rarely surpasses 3 centimetres. It is a walnut to dark rusty brown colour, though it becomes significantly dingy and greyish with age. Dried specimens will be very pale, usually a light buff with greyish tones. Three features are able to define this mushroom: it often presents with a low umbo, it features a separable pellicle that makes it sticky or slimy, and it has translucent striations near the edge when wet.
While the cap itself may have a subtle or absent bluing reaction to damage, blue and green-brown tones are more common on the stipe, especially near the base. The whitish stipe, sometimes slightly yellowish, is tough and cartilaginous. It can feature patches of fine hairs or “fibrils” as well as clumps of mycelium near the base. This mycelium is usually tangled with dried grass when picked fresh and can also feature a bluing reaction.
The transient or subtle bluing reaction is likely a consequence of the levels of alkaloids in P. strictipes. Psilocin, the primary contributor to the bruising common among Psilocybe, is likely in very low relative abundance. While the quantities of active compounds have not been assayed or confirmed, anecdotal evidence suggests a moderate to potent species. Evidence of recreational usage in North America bolsters this conclusion.
Aside from its recreational and medicinal features, P. strictipes may also have impacts on the environment. Along with other fungi, and even members of the Psilocybe genus, this species is being investigated for its capacity for bioremediation. It has been found to isolate or change certain harmful toxins, namely polycyclic aromatic hydrocarbons, that would otherwise be harmful to life.
Guzmán, Gastón, et al. “Psychotropic mycoflora of Washington, Idaho, Oregon, California and British Columbia.” Mycologia 68.6 (1976): 1267-1272.
Image by S. Poumarat.