Characters: Colonies consist of dense thickets of short cylindrical branches which may form extensive stands. Axial corallites are small. Radial corallites are irregular in size and shape; exsert corallites have prominent lower lips. Colour: Greyish-brown with white branch tips and white branch coenosteum. This colouration is only very distinctive in Japan. Similar species: Acropora tumida, which may have a similar growth-form but radial corallites are aligned along branches and do not have prominent lower lips. See also A. sekiseiensis and A. parahemprichii. Habitat: Shallow rocky foreshores or shallow reef flats. Abundance: May be locally dominant in Japan, rare elsewhere.