Colonies are flabello-meandroid with valleys completely separated. Sometimes living parts of colonies are separated by dead basal parts. Valleys are approximately 20 millimetres wide and divide infrequently. Primary septa are approximately 10 millimetres exsert and are rounded in shape. They plunge steeply within the valleys and do not form columellae. Polyps have mantles up to 50 millimetres wide which obscure the underlying septa. These mantles have elongate vesicles which vary greatly in degree of inflation.
Grey, usually with vesicles darker than mantles.