Characters: Colonies are arborescent with cylindrical branches but may be corymbose, with horizontally fused basal branches which have upturned ends. They may form stands more than 5 metres across. Branches are smaller than those of the large staghorn Acropora species. Radial corallites are of mixed sizes, with projecting lower lips. Colour: Pale to dark brown or blue, often with pale blue tips. Similar species: May superficially resemble Acropora formosa and A. yongei, but radial corallites are distinctive. Acropora aspera has similar radial corallites but these are much larger and more scale-like. See also A. loisetteae. Habitat: Usually restricted to shallow back-reef margins. Abundance: Usually uncommon but may be a dominant species.