Abstract
Drift fruits of Apocynaceae on the coast of Japanese Islands were studied. Three species were identified, Cerbera manghas, C. odollam and Ochrosia oppositifolia. Drift fruits of these species have been confused with each other, especially C. manghas and O. oppositifolia. Although typical fruits of these three species can be distinguished based in size, shape and character of fibrous mesocarp, it is often difficult to identified because their sizes were varied and different appearances of fruits by the floating period in seawater. It was clarified that the cavity of kernel or seed size and the wall thickness of endocarp, which can be seen by cross section of the drift fruit, differ among species.
