(Ellis & Solander, 1786)
Colonies form rounded, thin undulated blades that curve upward near the edges. Upper surface with high, rounded, concentric ridges and straight, wide, wavy valleys. The corallite centers are distinctively nestled in rows against the ridges' steep outer edges. The inner ridge faces slope more gently toward the colonies' centers. The underside of the colony is smooth, without polyps.
Shades of brown to gray, often with yellowish, greenish or bluish tints; outer edge of the blades often white.
Corallite diameter 2.0-2.9 mm, with 13-24 septa per corallite. Columella present, trabecular and discontinuous.
Inhabit deep reefs, between 15 and 75 m, but most common between 30 and 50 m.
Occasional Caribbean, not reported from Florida or the Bahamas.