Plocamium cartilagineum (Linnaeus) P.S.Dixon
Description: Narrow, compressed, cartilaginous, bright scarlet fronds, to 300 mm long, tufted, much divided. Branching irregularly alternate, pinnules alternately secund in twos to fives, with acute apices, lowest of each set a simple spur, others increasingly strongly pectinate.
Habitat: On rocks and Laminaria hyperborea stipes, lower intertidal and subtidal, abundant, widely distributed, often washed ashore in quantity, and persisting in the drift.
Similar species: Sphaerococcus coronopifolius and Plocamium maggsiae.