Multiple origins of two Ochrosia (Apocynaceae) species endemic to the Bonin (Ogasawara) Islands

•Ochrosia is widely distributed genus from the West Indian Ocean to the Middle Pacific.•Phylogeny of Ochrosia focused on the biogeography of island endemics is presented.•Two endemic species on the Bonin Islands had distinct phylogenetic origins.•The two endemic species were independently derived about 1–2 million years ago.•Complex origins of flora in oceanic islands are demonstrated.