Description
This brown seaweed is easily recognized because the stems, called thallus, is interrupted by large oval clubs. The thallus has no middle rib and the clubs are filled with gas. The smaller clubs, on stalks at either side of the thallus, are the reproductive organs.

Size
Thallus up to 1,5 m long.

Colour
Olive-coloured to yellowish green.

Habitat
On hard substrate, from shallow to a depth of about 8 meters.

Distribution
Entire north Atlantic, but also as an introduced species to the American west coast.