Vatanparast, M.; Takayama, K.; Tateishi, Y.; Kajita, T.

Geographic range is a key indicator of evolutionary success. While animals can move freely, plants primarily expand their range through long-distance seed dispersal. To investigate the maximum extend of seed dispersal in land plants, we studied Canavalia rosea (Sw.) DC. (Leguminosae), a species distributed throughout tropical and subtropical coastal areas worldwide. Population genetic analyses using six chloroplast regions and two low-copy nuclear loci from 436 individuals and 37 populations across the species\' range demonstrated that seed dispersal by ocean currents effectively maintains the global distribution of this species, though population structure is influenced by continental barriers. The results showed that the extensive range of C. rosea resulted from recent, long-distance seed dispersal within and across the Atlantic and Indo-Pacific oceanic regions, while the Isthmus of Panama has prevented gene flow among populations between these oceanic regions. These findings highlight the significant role of ocean currents in seed dispersal and plant biogeography.