Nereocystis luetkeana

''Nereocystis'' is a monotypic genus of kelp containing the species ''Nereocystis luetkeana''. Some common names include edible kelp, bull kelp, bullwhip kelp, ribbon kelp, giant kelp, bladder wrack, and variations on these names. It forms thick beds on rocks, and is an important part of kelp forests. It can grow to a maximum of 36 m . ''Nereocystis'' has a holdfast of about 40 cm , and a single stipe, topped with a pneumatocyst containing carbon monoxide, from which sprout the numerous blades. The blades may be up to 4 m long, and up to 15 cm wide. It is usually annual, sometimes persisting up to 18 months. ''Nereocystis'' is the only kelp which will drop spore patches, so that the right concentration of spores lands near the parent's holdfast. It is common along the Pacific Coast of North America, from Southern California to the Aleutian Islands, Alaska.