Colubrina oppositifolia, known as in Hawaiian, is a rare species of flowering tree in the family Rhamnaceae endemic to Hawaii.
This tree reaches a height of . The trunk is coated in shredding gray-brown bark and the smaller twigs are reddish. The leaves are oppositely arranged and have pointed oval blades. The yellow-green flowers occur in clusters of 10 to 12. The fruit is a rounded capsule which is explosively dehiscent.
It can be found in Hawaiian dry, coastal mesic, and mixed mesic forests at elevations of on the islands of Oahu (Waianae Range) and Hawaii (on the slopes of Kohala, HualÃÂlai, and Mauna Loa). There is also one individual remaining on Maui. Associated plants include (Psydrax odorata) and (Reynoldsia sandwicensis).
Native Hawaiians valued the hard wood of C. oppositifolia and that of a related species, Alphitonia ponderosa, both of which were known as . Consequently, the exact usage of C. oppositifolia wood is unknown. It is believed to have been used in (house posts), (round kapa beaters), (square kapa beaters), (harpoons), (fishing net shuttles), (javelins), (spears), (daggers), (clubs), leiomano (shark tooth clubs), (digging sticks), pieces for (a wand game), and (musical bows).
This tree has become very rare in the wild. Once a dominant species of the forests it inhabits, it has now been reduced to no more than 300 wild individuals. Threats to the species have included introduced plant species, herbivory by feral pigs and goats, rats, and the black twig borer (Xylosandrus compactus), an invasive insect. The hard wood made it valuable to people, who overharvested it. This is a federally listed endangered species of the United States.