Two new subspecies of Lasianthus inodorus (Rubiaceae) from Kinabalu, Borneo, and their biogeographical implication

Two populations from Mount Kinabalu, Borneo, are recognised as two new subspecies of Lasianthus inodorus Blume (Rubiaceae), which occurs in montane habitats in mainland Southeast Asia, Sumatra and Java. The species and its subspecies are considered to compose a particular taxonomic group in the genus. Ecology and biogeography of the species group are discussed with the historical explanation of the tectonic history of Cenozoic Southeast Asia. The example strongly supports the concept of floristic connections between Malesia and mainland Southeast Asia.