| 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: | - |