Characters: Colonies are corymbose clumps or cushions, with cushions occurring either singly or in groups. Main branches are short or absent. Branchlets are of uniform length and spacing. Axial corallites are short and tubular. Radial corallites are arranged in a neat rosette and are scale-like.
Colour: Always a uniform grey-brown.
Similar species: Acropora tenuis, which has pointed branchlet tips and less scale-like radial corallites. The rosette arrangement of radial corallites is similar to that of A. hyacinthus when viewed from above.
Habitat: Upper reef slopes.
Abundance: Common, especially in the western Indian Ocean.