This kelp is easily distinguished by its ruffled base (sporophyte), flat growth pattern, and unusual leaf pattern. It’s a popular food and an invasive species, from Japan. It can grow on almost any surface, and was first noticed in Monterey Harbor in 2001. Efforts to control this plant from overcrowding local habitats are encouraged, including making sure boats aren’t transporting it to other harbors. It’s commonly found on docks near the surface, where it can be easily removed, but can also be found growing on boats. It will grow down to 50 feet, and up to 3 feet in length.