Characters: Colonies are phaceloid. Corallites diverge from the colony base, or are irregular, or crowded if space is restricted. They are less than 10 millimetres diameter. Septa are exsert and irregular, with some septa thicker than others. Polyps are fleshy; thick septa give prominent radiating stripes to the upper corallite surface.
Colour: Brown or green with green oral discs.
Habitat: Protected reef slopes where the substrate is partly sandy. Forms extensive single species stands, sometimes over 5 metres across.
Taxonomic Note: The type species of Caulastrea Dana, 1846.