Molecular phylogenetics ofChelonopsis(Lamiaceae: Gomphostemmateae) as inferred from nuclear and plastid DNA and morphology

The recently established tribe Gomphostemmateae (Lamiaceae) consists ofGomphostemma, BostrychantheraandChelonopsis, but relationships within and between these genera have not been well studied. Only six of the approximately 46 species of Gomphostemmateae have been included in any previous phylogenetic analysis. In the present study, we used DNA sequences of two nuclear regions (ITS, ETS) and five plastid loci (psbA-trnH, rps16, trnLintron,trnL-trnFspacer,trnStrnG) to reconstruct the phylogeny of the East Asian genusChelonopsisfor the first time. The molecular results indicate that the tribe Gomphostemmateae is monophyletic;Bostrychantherais embedded inChelonopsis; andChelonopsiscomprises two clades, one encompassing the taxa ofChelonopsissubg.Chelonopsisand the genusBostrychantheraand the other consisting ofChelonopsissubg.Aequidens. This split is supported by several morphological characters. These results, which are further strengthened by morphological and cytological data, indicate thatBostrychantherashould be transferred toChelonopsis. In addition, our results show that withinC.subg.Aequidens, sect.Aequidensand sect.Microphyllumare monophyletic. Furthermore, two major clades are concordant with the Sino-Japanese and Sino-Himalayan distribution patterns.