Description: Thallus of this very common kelp is light to medium brown with a finely branched holdfast (haptera), a cylindrical stipe up to 50 cm (20 in) long without mucilage ducts, and a blade up to 3.5 m (10 ft) long. The blade is moderately thin and undulate and frequently has rows of blister-like swellings or puckers (bullations) near the base. Habitat: Although this kelp is considered a perennial, the blade dies back in the fall/winter and re-grows in the spring. It attaches to rock in the low intertidal to subtidal and prefers protected to semi-protected habitats. Similar taxa: Hedophyllum nigripes.