New polyps grow on short stolons and the coenosarc (soft tissue) does not cover the skeleton in a continuous sheet as it does in most coral species.

The septa of adjoining corallites are connected by wide, flat, granular costae (ridges).

[2] A. solitaria can be confused with the northern cup coral (Astrangia poculata) but that species usually forms clumps with more numerous, smaller corallites.

[1][2] This coral is found in sheltered shallow water but on a particular stretch of coast on Grand Cayman, a large onshore boulder was found to harbour the remains of numerous colonies of A. solitaria that were carbon-dated to an age of six hundred years.

This boulder was likely shifted onshore by a hurricane three hundred and thirty years ago, an event which would have resulted in the death of the corals.