Unexpected burst of new data on vascular plants flora for the Lesser Kuril Ridge and the whole Kuril archipelago

Flora of the southern Kuril continental islands is extremely diverse due to the complex history of geology and climate, fluctuating connections with other territories in the past, and the habitat diversity of the archipelago. It is likely well-investigated due to the long history of botanical studies, and floristic findings are expected only in taxonomically difficult plant groups. To test this assumption, we carried out a special investigation of the aquatic vascular plants on the Lesser Kuril Ridge (isl. Shikotan, Polonskogo, Yurii, Tanfilieva, Zelyonyi) and isl. Kunashir. In line with our expectations, we revealed nine taxa that have never been reported for the whole Kuril archipelago (including six new for Sakhalin floristic province of Russia: Potamogeton manchuriensis, P. x sparganiifolius, P. x variifolius, P. x vepsicus, Sagittaria aginashi, Sparganium subglobosum); all of them are aquatic ones. We found 24 species that are new for the Lesser Kuril Ridge or the whole Southern Kurils from which only about a half were aquatic. Unexpectedly, we found 53 mainly terrestrial species that are new for the Little Kurils (the Lesser Kuril Ridge with exception of isl. Shikotan), and substantially supplemented floristic lists of each island. (C) 2020 National Science Museum of Korea (NSMK) and Korea National Arboretum (KNA), Publishing Services by Elsevier.