Phylogeny of the Asian Hedyotis-Oldenlandia complex (Spermacoceae, Rubiaceae): Evidence for high levels of polyphyly and the parallel evolution of diplophragmous capsules

► Asian samples were increased for the phylogenetic analysis. ► Hedyotis s. str. and Oldenlandia s. str. were supported. ► Habit, stipule, and capsular dehiscent pattern have taxonomic value. ► Dimetia, Scleromitrion, and Thecagonum, were resurrected. ► Diplophragmous capsule evolved independently.