Oreocharis hainanensis (Gesneriaceae), a new species from karst regions in Hainan Island, South China

Oreocharis hainanensis, a new species of Gesneriaceae is described and illustrated from low-altitudual karst areas in Hainan Island, South China. The new species is easily distinguished from its closely-related O. jasminina by campanulate floral tube, zygomorphic corolla and exserted stamens. It also shows different habitats from the four currently-recognized Oreocharis taxa on the island. Molecular phylogeny analysis based on plastid trnL-trnF and nuclear ITS1/2 sequences supported the delimitation of the new species, which forms a monophyletic clade with all the other Oreocharis taxa from Hainan Island. The roles of habitat and floral isolation in the evolution of the new species and its affinities are discussed. The species was assessed as Vulnerable (VU C1 and D2) according to IUCN Red List Categories and Criteria.