Gardiner's Coral

zooxanthellate

Colonies are massive, reaching 1 m across. Calices are polygonal, not round, and 3 - 5 mm diameter. The inside walls appear to the naked eye to be smoothly concave surfaces because the septa are very numerous, close together and of uniform height. Tall corallite walls may surround a single or a dividing group of corallites. The species is common on reef slopes in clear to moderately turbid water, from near the reef crest in sheltered water to at least 25 m deep. (Sheppard, 1998 ) Colonies are massive to encrusting, sometimes with laminar margins. Corallites have poorly defined walls but are separated by acute ridges so that each corallite or group of corallites is at the bottom of a neat excavation. Columellae are present and septo-costae are very fine and even. Polyps are rarely extended and only at night. Colour: usually purple-grey, sometimes brown or yellow. Abundance: uncommon throughout its range except on some walls or under overhangs. Usually requires clear water. (Veron, 1986 ) Forms massive colonies with plate-like edges. Prominent ridges separate the polygonal corallites. Colour: usually green to brown. Habitat: diverse, in clear water. (Richmond, 1997)