liberty caps uk Psilocybe semilanceata
Scientific classification
Kingdom:	Fungi
Division:	Basidiomycota
Class:	Agaricomycetes
Order:	Agaricales
Family:	Hymenogastraceae
Genus:	Psilocybe
Species:	P. semilanceata
Binomial name
Psilocybe semilanceata (Fr.) P.Kumm. (1871)
Synonyms[1][2]
Agaricus semilanceatus Fr. (1838) Geophila semilanceata (Fr.) Quél. (1886) Panaeolus semilanceatus (Fr.) J.E.Lange (1936) Panaeolus semilanceatus (Fr.) J.E.Lange (1939)

Psilocybe semilanceata Mycological characteristics
	gills on hymenium
	cap is conical or umbonate
	hymenium is adnate or adnexed
	stipe is bare
	spore print is brown to purple
	ecology is saprotrophic
	edibility: psychoactive

Psilocybe semilanceata, commonly known as the liberty cap, is a species of fungus which produces the psychoactive compounds psilocybin psilocin and baeocystin. It is both one of the most widely distributed psilocybin mushrooms in nature, and one of the most potent. The mushrooms have a distinctive conical to bell-shaped cap, up to 2.5 cm (1 in) in diameter, with a small nipple-like protrusion on the top. They are yellow to brown, covered with radial grooves when moist, and fade to a lighter color as they mature. Their stipes tend to be slender and long, and the same color or slightly lighter than the cap. The gill attachment to the stipe is adnexed (narrowly attached), and they are initially cream-colored before tinting purple to black as the spores mature. The spores are dark purplish-brown in mass, ellipsoid in shape, and measure 10.5–15 by 6.5–8.5 micrometres.

The mushroom grows in grassland habitats, especially wetter areas. But unlike P. cubensis, the fungus does not grow directly on dung; rather, it is a saprobic species that feeds off decaying grass roots. It is widely distributed in the temperate areas of the Northern Hemisphere, particularly in Europe, and has been reported occasionally in temperate areas of the Southern Hemisphere as well. The earliest reliable history of P. semilanceata intoxication dates back to 1799 in London, and in the 1960s the mushroom was the first European species confirmed to contain psilocybin.

The possession or sale of psilocybin mushrooms is illegal in many countries.

liberty caps uk