Polyps are flat, with a slight central dome around the mouth. Septa are not thickened or exsert around the mouth. Small corals have an angular outline that becomes irregular when fully grown. They reach 90 millimetres diameter. Septa are thick and unequal. Tentacular lobes are absent. Costae are fine and only developed towards the polyp perimeter.
Brown, green or yellow. Small polyps often have six pale primary septa resembling spokes of a wheel.