Species:

Note: The species occurs naturally in northern Norway south to the Trondheimsfjord. However, it has spread southwards to some localities, e.g. to the Oslofjord, and is considered to be an introduced species in such localities. In the harbour of Bergen (Skuteviken and Sandviken) it was first recorded in 2007. The species can be difficult to separate from other Fucus species. It has no bladders, and an inconspicuous mid rib which may gradually disappear or fade towards the tip of the branch. It is fertile during spring, and carries swollen receptacles in the end of branches. Another characteristic feature is the occurrence of small, enclosed cavities in the cortex, caecostomata.