Many cacti are known to be psychoactive, containing phenethylaminealkaloids such as mescaline.[1] However, the two main ritualistic (folkloric) genera are Echinopsis, of which the most psychoactive species occur in the San Pedro cactus group (including Echinopsis pachanoi, syn. Trichocereus pachanoi, Echinopsis Peruviana, syn. Trichocereus peruvianus and Echinopsis lageniformis, syn. Trichocereus bridgesii[2][3]), and Lophophora, with peyote (Lophophora williamsii) being the most psychoactive species. Several other species pertaining to other genera are also psychoactive, though not always used with a ritualistic intent.[4][5][6]
^Pummangura, S.; J. L. McLaughlin; R. C. Schifferdecker (September 1981). "Cactus Alkaloids. XLVII. β-Phenethylamines From the "Missouri Pincushion", Coryphantha (Neobessya) missouriensis". J. Nat. Prod. 44 (5): 614–616. doi:10.1021/np50017a022.