Psilocybe yungensis is a species of psychedelic mushroom in the family Hymenogastraceae. In North America, it is found in northeast, central and southeastern Mexico. In South America, it has been recorded from Bolivia, Colombia, and Ecuador. It is also known from the Caribbean island Martinique, and China. The mushroom grows in clusters or groups on rotting wood. The fruit bodies have conical to bell-shaped reddish- to orangish-brown caps that are up to 2.5 cm (1.0 in) in diameter, set atop slender stems 3 to 5 cm (1.2 to 2.0 in) long. The mushrooms stain blue when bruised, indicative of the presence of the compound psilocybin. Psilocybe yungensis is used by Mazatec Indians in the Mexican State of Oaxaca for entheogenic purposes.