Phylum: Ochrophyta   Family: Cladostephaceae

Cladostephus spongiosus  (Hudson) C. Agardh, 1817

Hairy Sand Weed

An irregularly branched thallus with rhizoidal filaments in a spiral form (bit like horsetail), with sub-apical hairs. Grows on rocks in the inter-tidal and shallow sub-tidal. Common

References: 
Bunker, Brodie, Maggs & Bunker (2017) - Seaweeds of Britain and Ireland;
Newton (1931) - A Handbook of the British Seaweeds