Phylogenetic and conservation status of the endangered terrestrial orchid Nervilia nipponica (Orchidaceae) in Korea

► We analysed sequence data from the recently discovered populations of N. nipponica s.l. on Jeju Island, Korea, comparing them with data from the two polyphyletic taxa presently referred to the species in Japan. ► All Korean populations belong to N. nipponica s.s., the homotypic taxon hitherto considered endemic to Japan. ► Extremely low genetic diversity was detected within the Korean populations. ► Korean populations of N. nipponica are vulnerable to directional and stochastic environmental change, and are therefore in urgent need of sustained efforts to ensure their protection.