Cactus Coral

Colonies are massive, laminar or foliaceous, the latter usually being bifacial. Corallites have poorly defined walls. They are small shallow depressions, usually with a central columella, sometimes separated by ridges. Corallites are interconnected by prominent septo-costae. Except for P. explanulata, polyps are extended only at night (Veron (1986)). Colonies may be foliaceous or globular and often dominate coral communities. Typically with prominent septo-costae connecting adjacent corallites. Polyps usually extended at night (Richmond, 1997).