Abstract
BACKGROUND: Melastoma has undergone rapid species radiation during the last one million years, and circumscription of some species in the genus has remained controversial. Melastoma kudoi, an erect species narrowly endemic to central Taiwan was previously treated as a synonym of M. intermedium, a semicreeping hybrid between the erect species M. candidum and the creeping M. dodecandrum, making its identity questionable. We addressed this question based on molecular and morphological data. RESULTS: Phylogenetic analyses based on nrITS sequence data revealed that M. kudoi is most closely related to M. dodecandrum. Further analyses of six nuclear genes (cam, chi, gapC, gbss, tpi and vr) and two chloroplast markers (trnL-trnF and psbA) showed that M. kudoi is well diverged from its close relatives. Morphologically, it is also easily distinguished from related species by its erect habit, center-positioned stigma, and spreading, basally enlarged hairs on the hypanthium. CONCLUSIONS: Both molecular phylogenetic and morphological data suggest that M. kudoi is well separated from M. intermedium, M. dodecandrum, and O. scaberrima, and should be treated as a distinct species. Taxonomic treatment and detailed description of M. kudoi are provided.