Characters: Colonies are massive or encrusting to columnar, with a smooth or hillocky surface. Corallites are rounded and equal in size. Costae do not alternate strongly. There are 12 primary septa.
Colour: Usually uniform or mottled grey, brown or cream.
Habitat: All reef environments.
Taxonomic Note: A species complex.
Identification Guides: Veron (1986a); Sheppard and Sheppard (1991); Nishihira and Veron (1995); Coles (1996); Carpenter, Harrison, Hodgson et al. (1997); Pillay, Terashima, Venkatasami et al. (2002); Chan, Choi, McCorry et al. (2005); Pichon, Benzoni, Chaineau et al. (2010); Turak and DeVantier (2011b);