Acacia heterophylla 1.4 million years ago. "A. heterophylla" sequences nest within those of the more diverse "A. koa", making the latter species paraphyletic. Both species are descended from an ancestral species in Australia, presumably their sister species, "Acacia melanoxylon"; the means of dispersal to Hawaii and then to Réunion (the latter trip a distance of 18,000 km) is thought to have been seed-carrying by birds such as petrels (the seeds of these species are not adapted for prolonged immersion in seawater). Both species also have very similar ecological niches, which differ from that of "A. melanoxylon". Acacia heterophylla Acacia heterophylla, the highland
Acacia koaia It can be seen on ranch land in North Kohala, and at a small fenced exclosure outside of Waimea known as the "koaia" sanctuary. "Koaia" is one of the species being used to revegetate the island of Kahoolawe, which lost most of its plant life to overgrazing and ordnance testing. Native Hawaiians ground "koaia" leaves and bark with "auaukoi" ("Senna occidentalis") and "kikānia pipili" ("Desmodium sandwicense") stalks. The mixture was then hydrated and used in a steam bath to treat diseased skin. The wood of "koaia" is harder and more dense than that of "koa". It was used to make