The Flora of the Bonin (Ogasawara) Islands

The Bonin (Ogasawara) Islands are an oceanic island group more than 1000 km from the Japanese Archipelago. As in other isolated islands of the Pacific Ocean, their flora is rich in endemic taxa. These endemics are mostly either schizo- or aneuendemics and have chromosome numbers that are either identical to or slightly different from those of their adjacent relatives. Three genera, Callicarpa (Verbenaceae), Crepidiastrum (Compositae), and Pittosporum (Pittosporaceae), are discussed as examples of adaptive radiation within the Bonin Islands. These genera are dispersed by birds, which swallow the seeds and later deposit them in new areas. Like plants with similar dispersal in the Hawaiian or Galapagos Islands, plants with bird-internal dispersal seem to have been the most successful in undergoing adaptive radiation into diverse habitats in the Bonin Islands.