Characters: Colonies are thin laminae with widely spaced, irregular corallites. Corallites are immersed and have broad columellae. A large central corallite may be distinguishable. Costae are well developed and have exsert triangular teeth; there are deep pits where costae commence.
Colour: Usually grey-green, grey or brown.
Habitat: Vertical substrates with clear water at 10-40 metres depth.
Abundance: Sometimes common.