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 koa confirmed this close relationship; the estimated time of divergence is about 1.4 million years ago. "A. heterophylla" sequences nest within those of the more diverse "A. koa", making the latter paraphyletic. Both species are thought to be descended from an ancestral species in Australia, presumably their sister species, "Acacia melanoxylon". Dispersals most likely occurred via seed-carrying by birds such as petrels. Both species have very similar ecological niches, which differ from that of "A. melanoxylon". A closely related species, koaia or koaie ("A. koaia"), is found in dry areas. It is most easily distinguished by having smaller seeds that are