Where does psilocybin come from?

Shrooms, known as the Psilocybin mushrooms, are hallucinogenic mushrooms containing Psilocybin (C12H17N2O4P), a chemical that can impair some cognitive activity.

These 'Magic Mushrooms' grow in Southern Texas, almost all of Latin American countries, and the majority of South America, as well as Southern Asia and Australia.

Sources:

http://en.wikipedia.org/wiki/Psilocybin_mushrooms