Colonies form horizontal tables of spectacular dimensions. Some colonies are irregularly shaped, mostly either due to breakage of the original colony or to the formation of irregular clusters of plates. Plates are side or centrally attached and are composed of radiating, irregularly dividing, interlinked main branches re-linked occasionally by sub-branches. Axial corallites are small and tubular. Radial corallites are widely spaced, tubular, and strongly appressed.