Groups of domed column stumps. Colours vary from green to ochre (more often) depending on light. Upper corallites are densely distributed and clearly prominent but not as tightly packed and large as Great Star Coral’s (q.v.).  Tentacles usually extend at night, but may sometimes be partially extended during the day. Close-up views can be very deceptive: corallite/polyp diameter ranges from 3 to 5 mm.

NOTE: The species was until recently known as Montastraea annularis. It is part of a group that includes another two variations now known as Orbicella franksii (formerly Montastraea franksii, or Boulder Star Coral) and Orbicella faveolata (or Mountainous Star Coral). All three belonged to the Faviidae family, but this has now also been renamed to Montastraeidae (in other words what used to be designation is now transferred to family name). This being said, the vernacular names in English and French have remained unchanged.  

As the formation grows, corallites congregate towards the top of the stumps and as a consequence the lower vertical portions clearly tend to look abandoned and eventually eroded.