A global community of nature enthusiasts
photographing and learning about wildlife
The thallus of this common canopy-forming kelp has a richly branched holdfast (haptera) and a cylindrical stipe 10–36 m (33–118 ft) long, terminating in a single, gas-filled pneumatocyst from which the many blades, up to 10 m (33 ft) long, develop. Blade growth can reach 15 cm (6 in) per day. Reproductive patches (sori) develop on the blades and drop to the seafloor at maturity.
It grows on rock from the low intertidal to subtidal; it prefers semi-exposed habitats or high current areas.These were washed ashore in a beach near Piedras Blancas, CA.