Bladderwrack kelp is a widespread olive-green to yellowish-green seaweed (alga) that occurs, often in thick patches, upon rocks in the lower to middle intertidal zones from Alaska to California. This kelp has a flattened, erect and somewhat rigid body that is regularly dichotomously (into twos) branched. During its reproductive phase, this kelp produces swollen receptacles at the tips of the branches, where the reproductive cells are produced.