Original paper

The misunderstood Cleistocactus serpens, and C. longiserpens, a new name for a species of Cactaceae from Peru

Leuenberger, Beat; Ernst,

Abstract

The taxonomic history of Cactus serpens, the basionym of Cereus serpens, Cleistocactus serpens, Bolivicereus serpens, Borzicactus serpens and Borzicactella serpens, is analysed. The combination Cleistocactus serpens is of particular interest because WEBER explicitly mentioned the original material in the HUMBOLDT & BONPLAND herbarium at Paris (P-Bonpl). The examination of the protologue and of the type material (flower only) leads to the conclusion that Cactus serpens is the same as Borzicactus neoroezlii F.Ritter. Cactus serpens has been twice misapplied. It is not the taxon listed by HUNT as Cleistocactus serpens including various heterotypic synonyms (as Loxanthocereus). For two of these, the necessary combinations Cleistocactus granditessellatus and C. sulcifer are provided. Cactus serpens is neither the same as the creeping plant with stem-born roots from Peru treated as Cleistocactus serpens by BACKEBERG and by RAUH, as Borzicactus serpens by KIMNACH, introduced into cultivation by RITTER originally under a nomen nudum, and later classified as Borzicactella serpens. This taxon is without an applicable name and is described here as a new taxon, Cleistocactus longiserpens.