Acacia heterophylla

Acacia heterophylla is an evergreen tree that typically grows to a height of up to 25 m (82 ft), sometimes a shrub at altitudes above 2,000 m (6,600 ft) and has longitudinally fissured bark and an often twisted trunk. Its phyllodes are thickened, flattened, elongated and arched with entire edges and longitudinal veins. The flowers are borne in spherical heads in racemes in axils or on the ends of branches, each head with 30 to 40 pale yellow flowers. Flowering occurs from June to November, and the pods are about 100 mm (3.9 in) long with five to ten seeds.

Genetic sequence analysis has shown its closest relative is Acacia koa of Hawaii; 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 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.

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