Home at last III: Transferring Uechtritzia and Asian Gerbera species into Oreoseris (Compositae Mutisieae)

摘要

Recently the Asian Gerbera species were shown to form a clade that was not the sister group of the African Gerbera. In this study, the position of the Asian Gerbera species was further assessed based on morphology and molecular phylogenetic analyses that included six Asian Gerbera and 26 other species from the Gerbera-complex. Morphological results showed that the six Asian Gerbera species, which were sampled, bear leaves with the adaxial epidermal surface lacking stomates, possess bracteate scapes and lack inner ray florets. These characters suggest that the Asian Gerbera species are most closely related to the species of Uechtritzia, which also share similar pollen grain size and shape with the Asian Gerbera, rather than to the African Gerbera. Furthermore, the phylogenetic results based on two nuclear (ITS and ETS) and three chloroplast (trnL–trnF, trnL–rpl32 and trnC–petN) sequences strongly support the Asian Gerbera and Uechtritzia forming a clade, with the latter nested within the Asian Gerbera species. Both morphological and molecular phylogenetic data thus confirmed the taxonomic identity of the Asian Gerbera and Uechtritzia. The authors herein formally treat the nine species of the Asian Gerbera and the three species of Uechtritzia as members of the genus Oreoseris, which is the earliest generic name of this lineage and has the nomenclatural priority.