Smooth holdfast (2 to 4 cm diameter) gives rise to a flattened, thin stipe. Younger plants are densely fringed with hairs. In mature plants, a prominent midrib is visible with opposite veins leading to and apparent on branches. Several orders of branching are seen with final branches appearing as spines or hairs. Plants are usually golden brown/green growing 1.5 m (up to 8 m) tall and with blades 2 to 3 cm wide. In juveniles, finer stipes, blades, and higher density of hairs are apparent. SAMPLING CODE NOTES: DEBL = Blade; DEHO = Holdfast; DELI = any size individual. Formerly Desmerestia ligulata.

This species can be locally abundant, found growing on rocks in the low intertidal zone to 15 meters subtidally. Plants are usually annual, while some may be perennial.

Alaska to South America. Widely distributed in Northern Hemisphere.