Phylum: Rhodophyta   Family: Corallinaceae

Jania rubens (Linnaeus) J.V. Lamouroux, 1816

Slender-beaded Coral Weed

One of the calcified seaweeds of the lower intertidal. Pinkish in colour but fading to white. Epiphytic, on Cladostephus and Cystoseira. A south and west distribution, infrequently recorded this far north

References: 
Irvine & Chamberlain - Seaweeds of the British Isles, Volume 1 Rhodophyta, Part 2B Corallinales, Hildenbrandiales;
Bunker, Brodie, Maggs & Bunker (2017) - Seaweeds of Britain and Ireland