Ochrosia is a genus of flowering plants in the family Apocynaceae (order Gentianales), first described in 1789. The genus comprises shrubs and small trees distributed across a remarkably broad Indo-Pacific range, from Southeast Asia and Australia to the islands of the Indian Ocean and throughout the Pacific Ocean basin, including Hawaii, New Caledonia, the Marquesas, Réunion, Mauritius, the Seychelles, the Philippines, Borneo, New Guinea, the Solomon Islands, and various island groups of Japan.
Members of Ochrosia belong to the dogbane family, which is noted for its latex-bearing tissues and, in many genera, the production of alkaloids. The genus is part of the tribe Vinceae within Apocynaceae. Several Hawaiian species are known by the native name Hōlei and include taxa that are either endangered or already extinct in the wild, reflecting the vulnerability of island-endemic plants. Ochrosia borbonica, native to Réunion and Mauritius, is among the more widely recognised species and has become naturalised in parts of southern China.
Some species formerly placed in Ochrosia have been reclassified into the related genus Rauvolfia, illustrating the ongoing refinement of circumscription within this part of Apocynaceae.
Etymology
The genus name Ochrosia derives from the Greek word ōchros (ὠχρός), meaning "pale yellow" or "ochre", a reference to the colour of the fruits or wood in some species. The name was established by Antoine Laurent de Jussieu in 1789.
Distribution
Ochrosia is native to Southeast Asia, Australia, and numerous islands of the Indian and Pacific Oceans, with species recorded from Hawaii, New Caledonia, the Marquesas, Réunion, Mauritius, the Seychelles, Borneo, the Philippines, New Guinea, the Solomon Islands, Queensland, New South Wales, and island groups of Japan (Ryukyu, Bonin, and Volcano Islands). Several species have also become naturalised in Guangdong province of China and Taiwan. Some island-endemic species, particularly in Hawaii and the Marquesas, are extinct or critically endangered in the wild.
Conservation
Several Hawaiian species of Ochrosia are of conservation concern: Ochrosia kilaueaensis is listed as extinct, and Ochrosia brownii from the Marquesas is noted as extinct in the wild. The broader Hawaiian Hōlei species (O. compta, O. haleakalae, O. kauaiensis) are restricted to individual islands and face pressures typical of Hawaiian endemic flora.
