Floristic findings on the Onekotan island clarify biogeographic subdivision of the Northern Kurils (Russian Far East)

Floristic subdivision of the northern part of the Kuril archipelago (Russian Far East) remains controversial. Such uncertainty in biogeographical subdivision could be caused by insufficient floristic data due to poor accessibility of mainly uninhabited northern Kuril islands. We aimed to explore the flora of the largest uninhabited northern Kuril island Onekotan to clarify its position in floristic subdivision. All the 19 species that we added to the known flora of Onekotan island grow on Paramushir and often on some other northern Kurils. Additionally, we revealed two species (Minuartia rubella and Poa lanata) that are new for the whole Kuril archipelago. Our findings demonstrated that floristic similarity between Onekotan and the both large northern continental Kuril islands (Shumshu and Paramushir) is higher than it was demonstrated before. However, discussion of floristic subdivision of the Northern Kurils is premature unless all the islands are sufficiently studied.