Interpretation and typification of Cactus opuntia L., Opuntia vulgaris Mill., and O. humifusa (Rafin.) Rafin. (Cactaceae)

SummaryLeuenberger, B. E.: Interpretation and typification of Cactus opuntia L., Opuntia vulgaris Mill., and O. humifusa (Rafin.) Rafin. (Cactaceae). — Taxon 42: 419–429. 1993. — ISSN 0040–0262.The taxonomic history of the controversial names Cactus opuntia and Opuntia vulgaris is discussed, the original elements associated with them are analysed, and the changing interpretation of the names by previous authors is reviewed. The consequences of the possible choices of a lectotype for nomenclatural stability are considered. Lectotypification of Cactus opuntia with material mentioned by previous authors would perpetuate the confusion surrounding this name and the homotypic Opuntia vulgaris based on it, as the latter name has been widely applied to two different species (O. humifusa and O. monacantha). Lectotypification of Cactus opuntia with another element involved, as here proposed, permits to sink the controversial names in the synonymy of Opuntia ficus‐indica, thereby avoiding the necessity of proposals to formally reject them. The correct names for the two species formerly known as “O. vulgaris” are O. humifusa, and O. monacantha. A neotype is designated for O. humifusa.