What is the scientific name or taxonomic classification of the poisonous plant Peyote?

There are not many street names for peyote compared to other substances. This is likely due to the difficulty obtaining peyote, since it grows slowly and only in a limited range in the wild. However, some slang terms may be mescal (not to be confused with the alcoholic beverage of the same name), buttons, mecalito, and big chief.