Species:

Note: The species grows intertidally in brackish water. In Norway it typically grows in river mouths, and has a patchy distribution along the coast. Thallus may be up to 30 cm long, is repeatedly dichotomously divided and flat, thin and flexible, It does not carry bladders, but may have inflated parts of thallus. The mid rib is clearly visible. The branches have variable width, even within one individual. The species is dioecious. The receptacles, which form in the end of branches, are likewise of variable shape, but are often dichotomously divided and very pointed.