Psilocybe tampanensis is a very rare psychedelic mushroom in the family Hymenogastraceae. Originally collected in the wild in a sandy meadow near Tampa, Florida, in 1977, the fungus would not be found in Florida again until 44 years later. The original Florida specimen was cloned, and descendants remain in wide circulation. The fruit bodies (mushrooms) produced by the fungus are yellowish-brown in color with convex to conic caps up to in diameter atop a thin stem up to long. Psilocybe tampanensis forms psychoactive truffle-like sclerotia that are known and sold under the nickname "philosopher's stones". The fruit bodies and sclerotia are consumed by some for recreational or entheogenic purposes. In nature, sclerotia are produced by the fungus as a rare form of protection from wildfires and other natural disasters. Taxonomy The species was described scientifically by Steven H. Pollock and Mexican mycologist and Psilocybe authority Gastón Guzmán in a 1978 Mycotaxon publication. According to Paul Stamets, Pollock skipped a "boring taxonomic conference" near Tampa, Florida to go mushroom hunting, and found a single specimen growing in a sand dune, which he did not recognize. Pollock later cloned the specimen and produced a pure culture, which remains widely distributed today. The type specimen is kept at the herbarium of the Instituto Politécnico Nacional in Mexico. Guzmán classified P. tampanensis in his section Mexicanae, a grouping of related Psilocybe species characterized primarily by having spores with lengths greater than 8 micrometers. Description The cap ranges in shape from convex or conic with a slight umbo, expanding in age to become flattened or with a slight central depression; it reaches diameters of . The surface is smooth, not striate (grooved), ochraceous brown to straw brown, buff to yellowish-grey when dry, with slight bluish tones at the margin, hygrophanous, and somewhat sticky when wet. The gills are more or less adnate (broadly attached to the stem slightly above the bottom of the gill, with most of the gill fused to the stem) and brown to dark purple brown in color with lighter edges. The stem is long, thick, and equal in width throughout to slightly enlarged near the base. There are fibrils near the top of the stem. The partial veil is cortinate (cobweb-like, similar to the partial veil of Cortinarius species), and soon disappears. The flesh is whitish to yellowish, and bruises blue when injured. The taste and odor are slightly farinaceous (similar