any of several genera of corals of the order Gorgonacea (phylum Cnidaria), characterized by a long, whiplike growth and a variety of bright colours. The “whip” consists of a colony of tiny polyps (cylindrical, stalklike forms with a mouth and eight tentacles at the upper, or free, end) that grow upon one another in a continuous single stem. Spicules, or needlelike structures, of lime embedded in the polyp body provide a firm but flexible support.