It often flourishes in exposed conditions. Occasionally found on mollusc shells or macroalgae such as Furcellaria . Corallina officinalis consists of calcareous, branching, segmented fronds, usually erect, up to 120mm high but often much shorter. Fronds rise from a calcareous crustose, disk shaped, holdfast about 70mm in diameter. Fronds consist of a jointed chain of calcareous segments, each becoming wedge shaped higher up the frond.
Branches are oppposite, resulting in a featherlike appearance.
Colour varied, purple, red, pink or yellowish with white knuckles and white extremities. Paler in brightly lit sites. Reproductive organs are urn shaped, usually borne at the tips of the fronds but occassionally laterally on segments. Distinguished from the similar Corallina elongata by the structure of its reproductive bodies which bear horns or antennae and from Jania rubens which branches dichotomously. Tyler-Walters, H., 2000.