Psilocybin mushrooms are a family of psychoactive fungi that contain psilocybin, a psychedelic substance of the tryptamine class. Psilocybin mushrooms occur on all continents and have been taxonomically classified into over 200 species, the most potent of which belong to the genus Psilocybe, the most common psychedelic mushroom and average user encounters. Other notably potent species include Panaeolus, Inocybes, Copelandia, and Gymnopilus.