Five new genera and revival of a genus based on molecular phylogenetic and morphological evidence in Trichosporeae (Gesneriaceae)

The tribe Trichosporeae is the most species-rich, systemically complex, and morphologically diverse tribe in the Old World Gesneriaceae. It has long been a focal point and a challenge in the phylogeny of Trichosporeae, with frequent unclear relationships and delimitations among a lot of genera. Here, we conducted a molecular phylogenetic analysis by employing nine DNA fragments with a high sampling coverage for key clades in the tribe Trichosporeae. Meanwhile, we carried out a comprehensive morphological and anatomical investigation on vegetative and floral organs in related genera and species, and try to uncover morphological synapomorphies associated with molecular clades. Our results demonstrated a well-supported phylogeny of major clades in the tribe, strongly corroborated by morphological data. We find that some genera, such as Raphiocarpus, Briggsia, and Boeica, are not monophyletic. Based on molecular phylogenetic and morphological analyses, we established five new genera and revived a genus in the tribe Trichosporeae, including Neoraphiocarpus, Macrophyllaea, Hispidopalata, Pseudobriggsia, and Kaiyua with revival of Boeicopsis. We further redefined the genera Raphiocarpus and Briggsiopsis. Our results would deepen our understanding about the phylogeny of the Old World Gesneriaceae.