Characters: Colonies are encrusting, thick plates, or columnar. They have a smooth surface and may be large, with columns up to one metre high. Corallites have alternating long and short fine septal spines. Tips of polyp tentacles are truncated giving a squared appearance. Sometimes six large tentacles alternate with six small tentacles. Colour: Uniform pale or dark brown. Similar species: Alveopora spongiosa, which is less columnar, does not have truncated tentacles, and has less clearly alternating septa. Habitat: Protected upper reef slopes. Abundance: Relatively common in the western Indian Ocean.