Phylum: Rhodophyta   Family: Furcellariaceae

Furcellaria lumbricalis (Hudson) J.V. Lamouroux, 1813

Clawed Fork Weed

Not as red as some 'red seaweeds', showing greenish-brown to black depending on age and weathering. Very similar to Polyides rotundus but usually with darker colouring, a rhizoidal holdfast and acute apices. Common attached to rocks in the mid to lower intertidal zone

References: 
Fish & Fish (2011) - A Student's Guide to the Seashore;
Bunker, et al - Seaweeds of Britain and Ireland;
Hiscock (1986) - A Field Key to the British Red Seaweeds