Jr., Inocencio E. Buot

The Philippine populations of Ochrosia oppositifolia (Lam.) K. Schum. (Apocynaceae) are restricted only to three localities in Western Philippines: Basilan Island, Zamboanga Peninsula and Lubang Island, Occidental Mindoro. Such range of distribution indicates that the Philippine populations may have originated from Western Malesia region where the plant is widely distributed. The fruit morphology of this plant suggests hydrochore dispersal with long dispersal ability. However, the limited range of distribution of O. oppositifolia in the Philippines implies that the species is possibly a late emigrant into the Philippine Islands with the other species from Western Malesia such as Artocarpus superba Beccari, Mallotus miquelianus (Scheff.) Boere., Mezoneurum sumatranum (Roxb.) W. & A. and others. The presence of the postulated Borneo-Palawan and Borneo-Sulu land bridges during the Pleistocene (1.6 million years B. P.) and the Recent (10 thousand years B. P. ) may have greatly aided plant dispersal by serving as corridor and temporary habitat of plants during the course of migration to the Philippine Archipelago.