This small octocoral forms an encrusting network of 2mm wide, flattened stolons on rocks and shells. Sometimes the stolons fuse to form a continuous sheet. The polyps are up to 10mm tall including tentacles, semi-translucent white. The stolon is typically red but may be yellow or colourless. Compare with Cornularia cornucopiae. If identification is still uncertain observe with a good magnifying glass: the stolon contains numerous minute calcareous particles (sclerites or spicules) about 0.1mm long; these are absent from Cornularia.