Abstract:Historically, the Hedyotis species with tetragonal stems and capitated inflorescences in China have often been identified as H. uncinella, and this name also included three heterotypic names synonymized by different taxonomists. Because this group of plants has many differences in leaf morphology, petiole length, inflorescence and pedicel length, etc., it seems to be unreasonable to lump them together into one species generally. Based on morphological comparison on type materials, field observation to morphological variation pattern in populations, and molecular phylogenetic analysis, the plants previously misidentified as H. uncinella include six taxonomic entities. Of which, H. borrerioides, H. cephalophora and H. kuraruensis should be reinstated, and the historically misidentified species of H. uncinella, the continuously overlooked species of H. linearifolia, as well as the newly recorded species of H. multiglomerulata are taxonomically distinct taxa. A key to classify these morphologically similar taxa is provided to facilitate taxonomic identification.
