Linnaeus, 1758 
It is primarily found growing around the rims of tide pools, but can be found in shallow crevices anywhere on the rocky shore that are regularly refreshed with sea water. It predominantly grows on the lower shore, especially where fucoid algae are absent, but is also found further up shore on exposed coasts.
It forms calcium carbonate deposits within its cells which serve to strengthen the thallus. These white deposits cause the seaweed to appear pink in colour, with white patches where the calcium carbonate is particularly concentrated, such as at the growing tips. The calcium carbonate makes it unpalatable to most rocky shore grazers.
The thallus of C. officinalus is firmly attached generally to rock and grows in tufts to a length of 120mm. It has pinnate branching with successive opposite lateral branches. Each frond consists of cylindrical calcified stipes which show segments each a little longer than broad, rising from a crustose base like a string of beads becoming larger and more wedge-shaped higher up the stipe.
Corallina grows on rocks in rock pools and occasionally on shells or other algae, at mid-littoral to 33m deep, it provides a habitat for many small animals which feed on the microorganisms dwelling in its dense tufts.
C. officinalis is found on solid rock on the North Atlantic coast, from northern Norway to Morocco, and intermittently from Greenland to Argentina. Corallina is also found in USA, Argentinaand elsewhere including some parts of Japan, China and Australasia.
- World Register of Marine Species
- Newton, L. 1931. A Handbook of the British Seaweeds. British Museum (Nat. Hist.) London
- Dickinson, C.I. 1963. British Seaweeds The Kew Series. Eyre & Spottiswoode.
- Irvine, L.M. & Chamberlain, Y.M. 1994. Seaweeds of the British Isles. Vol. 1 Rhodophyta. Part 2B. Corallinales, Hildenbrandiales. HMSO.ISBN 0 11 310016 7
- Lewis, J.R. 1964. The Ecology of Rocky Shores. The English Universities Press Ltd, London
- M. D. Guiry & Wendy Guiry (2007-01-25). "Corallina officinalis Linnaeus". AlgaeBase.