Colonies are thick plates or hemispherical and are frequently over one metre across. Valleys are short, broad (up to 20 mm), V-shaped and have sharp upper margins. Septa are usually thin and slope uniformly to the columellae, which usually form well defined centres. Paliform lobes may be present. Columellae are weakly developed.
Uniform grey or with brown walls and pale cream or pink valley floors.
Most reef environments, but especially in lagoons.