Caryopteris (Lamiaceae) and the conflict between phylogenetic and pragmatic considerations in botanical nomenclature

The delimitation of Caryopteris (Lamiaceae) exemplifies thr conflict betwee n the representation of monophyletic groups and pragmatic concerns in Linna ean classification. Cladistic analyses of nonmolecular (mainly morphologica l) data and chloroplast DNA (rbcL and ndhF) sequences were performed to tes t the monophyly of the eastern Asian genus Caryopteris. The results corrobo rate earlier studies indicating that Caryopteris is either para-or polyphyl etic. if paraphyletic, other genera whose sister groups lie within the curr ently accepted limits of Caryopteris include Trichostema, Rubiteucris, and probably Ajuga, Schnabelia, and Amethystea. Because phylogenetic resolution is too poor to refer all of the species of Caryopteris to well supported c lades, a choice must be made between recognizing a paraphyletic genus or se veral monotypic ones,three of which would comprise morphologically quite si milar species. A compromise solution is adopted in which three new genera a re described (Pseudocaryopteris, Discretitheca, and Tripora), the latter tw o monotypic, and four species of Caryopteris are transferred to other gener a, one of which may not be monophyletic. Nine new combinations are provided : Discretitheca nepalensis, Pseudocaryopteris bicolor, Pseudocaryopteris fo etida, Pseudocaryopteris paniculata, Rubiteucris siccanea, Schnabelia aureo glandulosa, Schnabelia nepetifolia, Schnabelia terniflora, and Tripora diva ricata. For comparative purposes, an alternative classification is provided that employs de Queiroz and Gauthier's phylogenetic system of nomenclature . Using this system, no new names are required, and all supraspecific taxa are both monophyletic and easily recognizable.