Phylum: Ochrophyta   Family: Laminariaceae

Laminaria hyperborea  (Gunnerus) Foslie, 1884

Forest Kelp

Also known as Cuvie, it grows on rocky substrata in the subtidal zone. It has a much stiffer stipe than Oarweed and stands erect at low water. A haven for many species and food for others

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