Aspect: White or beige bush with numerous elongated branches. The ensemble can look very dense when polyps are extended as exemplified by the above picture. Population: Common. Notable feature: Owes its debatable designation to the fact that polyps retract absolutely flush with the surface of the branch, only leaving a light trace that gives the impression of a porous scar. Environment: Tends to settle in open waters on a solid rock base. Behaviour: -
