Colonies are phaceloid, rarely subplocoid. Corallites are 9-14 millimetres diameter. Septa are not arranged in cycles and are numerous. They have small blunt teeth. Mantles, but not tentacles, are extended during the day and may form a continuous surface obscuring the underlying growth-form.
Mantles are usually dark grey, but may be red or green. Oral discs are usually green but may be red or dark grey.
Lower reef slopes protected from wave action, and turbid environments.