Colonies are flat to hemispherical and may be over 5 metres across. Several colonies (which may be different colours and have polyp mantles of different texture) may grow together to form a single composite stand. Colonies are phaceloid to flabello-meandroid, the latter with valleys dividing irregularly as growing space permits. Septa taper in thickness from the wall to the columella and have tall sharp teeth. Retracted polyps are thick and fleshy, with either smooth or rough mantles.
Uniform in colour or with two or more colours concentric to mouths or valley walls. All corallites of the same colony have the same colours.
Upper reef slopes.
Frequently a dominant species and may form extensive single species stands.