A colony of Antipathes dichotoma can grow to a height of 1 m (3 ft 3 in) or more. It forms a sparsely branching structure with slender, flexible branches arranged irregularly around the trunk. The angle at which the branches project is variable but is often nearly 90°. The smaller branches bear four to six rows of short, smooth conical spines. The polyps are 2 to 2.4 mm (0.08 to 0.09 in) in diameter with three or four polyps per centimetre. They are arranged in a single series on the smallest branches and in multiple series on the largest ones. There is considerable variation in appearance of neighbouring colonies and in different parts of the same colony. Learn more about Black Coral