ALLOZYME DIVERSITY AND THE EVOLUTION OF SYMPLOCOS (SYMPLOCACEAE) ON THE BONIN (OGASAWARA) ISLANDS

To study the origin and speciation of plants in oceanic islands, elect rophoretic analyses have been done on three endemic species of Symploc os in the Bonin Islands as well as on three other species; S. kuroki, S. nakaharae and S. tanakae which are considered to be closely related to the Bonin endemics. There occur three species: S. kawakamii, S. pe rgracilis and S. boninensis in Bonin. The genus Symplocos is one which is considered to be diversified in the Bonin Islands. Seven enzyme sy stems presumed to be encoded by 18 loci were examined. The genetic div ersity was low in the island species, as reported in some oceanic isla nd plants of Hawaii and the Bonin Islands. The three endemics share hi gh genetic identities and they clustered together in the tree drawn by the DPGMA method, suggesting that they are a monophyletic group, that is, they result from a single introduction.