Characters: Colonies are massive and divided into parallel or irregular ridges or hillocks. They form some of the largest massive colonies of all corals, yet skeletons are dense indicating a slow growth rate. Corallites are small, giving colonies a smooth appearance. They have strongly alternating septo-costae. Colour: Usually uniform grey, sometimes brown. Similar species: Corallites are like Pavona clavus but smaller, with more exsert primary septo-costae. See also P. minuta. Habitat: Most reef environments and forms large colonies on horizontal shallow substrates. Abundance: Uncommon but conspicuous. Rare in the Red Sea.