Psilocybin mushrooms are fungi

Fungus

A fungus is a member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds , as well as the more familiar mushrooms. These organisms are classified as a kingdom, Fungi, which is separate from plants, animals, and bacteria...

 that contain the psychoactive compounds psilocybin

Psilocybin

Psilocybin is a naturally occurring psychedelic prodrug, with mind-altering effects similar to those of LSD and mescaline, after it is converted to psilocin. The effects can include altered thinking processes, perceptual distortions, an altered sense of time, and spiritual experiences, as well as...

 and psilocin

Psilocin

Psilocin , an aromatic compound, sometimes also spelled psilocine, psilocyn, or psilotsin, is a psychedelic mushroom alkaloid. It is found in most psychedelic mushrooms together with its phosphorylated counterpart psilocybin...

. There are multiple colloquial terms for psilocybin mushrooms, the most common being shrooms or magic mushrooms.

Biological genera

Genera

Genera is a commercial operating system and development environment for Lisp machines developed by Symbolics. It is essentially a fork of an earlier operating system originating on the MIT AI Lab's Lisp machines which Symbolics had used in common with LMI and Texas Instruments...

 containing psilocybin mushrooms include Agrocybe

Agrocybe

Agrocybe, including edible fungi such as the Agrocybe cylindracea, is a genus of mushroom with similar characteristics to the Tricholoma matsutake, Agrocybe aegerita and Agrocybe parasitica. Some are poisonous mushrooms...

, Conocybe

Conocybe

The genus Conocybe is a genus of mushrooms consisting of Conocybe tenera and at least 243 other species, with at least 50 species in North America....

, Copelandia

Copelandia

Copelandia is a genus of mushrooms consisting of at least 12 species. Most Copelandia species have a long, thin fragile stem and are delicate, growing in grasslands on dead moss, dead grass, sand dunes, decayed wood, and dung. They are found in the tropics and neotropics of both hemispheres...

, Galerina

Galerina

Galerina is a genus of small brown-spored saprobic mushrooms, with over 300 species found throughout the world, from the far north to remote Macquarie Island in the Southern Ocean. Species are typically small and hygrophanous, with a slender and brittle stem. They are often found growing on wood,...

, Gerronema

Gerronema

Gerronema is a genus of small- to medium-sized lignicolous agarics with white, nonamyloid, basidiospores and decurrent lamellae. The genus, first described by American mycologist Rolf Singer in 1951, contains 13 species.-Description:...

, Gymnopilus

Gymnopilus

Gymnopilus is a genus of gilled mushrooms within the fungal family Strophariaceae containing about 200 rusty-orange spored mushroom species formerly divided among Pholiota and the defunct genus Flammula. The fruiting body is typically reddish brown to rusty orange to yellow, medium to large,...

, Hypholoma

Hypholoma

Fungi of the genus Hypholoma are quite well known due to the commonness of Sulphur Tuft on stumps in temperate woodlands. This species is easily recognizable because the dark spores create a distinctive greenish effect on the yellow cap underside...

, Inocybe

Inocybe

Inocybe is a large, complex genus of mushrooms. Members of Inocybe are mycorrhizal, and some evidence shows that the high degree of speciation in the genus is due to adaptation to different trees and perhaps even local environments.-Description:...

, Mycena

Mycena

Mycena is a large genus of small saprotrophic mushrooms that are rarely more than a few centimeters in width. They are characterized by a white spore print, a small conical or bell-shaped cap, and a thin fragile stem. Most are gray or brown, but a few species have brighter colors. Most have a...

, Panaeolus

Panaeolus

Panaeolus is a genus of small, black-spored, saprotrophic agarics. The word Panaeolus is Greek for "all variegated", alluding to the spotted gills of the mushrooms produced.- Characteristics :...

, Pluteus

Pluteus

Pluteus is a large genus of fungi with over 100 species. They are wood rotting saprobes with pink spore prints and gills that are free from the stem.Pluteus means shed or penthouse.-Characteristics of the genus :...

, and Psilocybe

Psilocybe

Psilocybe is a genus of small mushrooms growing worldwide. This genus is best known for its species with psychedelic or hallucinogenic properties, widely known as "magic mushrooms", though the majority of species do not contain hallucinogenic compounds...

. There are approximately 190 species of psilocybin mushrooms and most of them fall in the genus Psilocybe.
There is some archaeological evidence for the use of psyilocybin-containing mushrooms in ancient times.