Aim: While many phylogeographical studies have focused on continental refugia, the function of islands as refugia has been long overlooked. In this study, we examined the biogeographic history of Microtropis japonica and its insular distribution to elucidate the hidden status of islands on the range expansion of plants. Location: Two disjunct island areas of Japan (the Izu and Ryukyu Islands) and their adjacent areas (the Japanese mainlands Honshu and Kyushu, and Taiwan). Taxon: Microtropis japonica...