Lessonia

a genus of brown algae of the order Laminariales. There are five species, distributed primarily in the cold and temperate seas of the southern hemisphere, where they form true underwater forests. In the northern hemisphere there is one known species, which is found in the Sea of Okhotsk. The thallus reaches a length of 4 m and is branched, with rhizoids at the base and plates at the ends of the branches.