It occurs in many kind of fungi and mushrooms , most notably Psilocybin mushrooms . Possession and use of psilocybin mushrooms , including the bluing species of Psilocybe , is therefore prohibited by extension . However , in many national , state , and provincial drug laws , there is a great deal of ambiguity about the legal status of psilocybin mushrooms and the spores of these mushrooms , as well as a strong element of selective enforcement in some places .