Description: Thallus is medium to dark brown with a large disc- or suction-cup-like holdfast, a somewhat rigid stipe up to nearly 1 m (37 in) long although it is often shorter, and a thick blade that can be nearly as wide as long. The blade is usually split and has mucilage ducts, which are visible microscopically. Habitat: This perennial kelp is found on rock in the extreme low intertidal to subtidal zones from semi-protected to exposed habitats. Similar taxa: Laminaria solidungula, Saccharina spp.