Kelp
Kelps are large brown algae seaweeds that make up the order Laminariales. There are about 30 different genera.
Kelp
In most kelp, the thallus (or body) consists of flat or leaf-like structures known as blades. Blades originate from elongated stem-like structures, the stipes. The holdfast, a root-like structure, anchors the kelp to the substrate of the ocean.
Gas-filled bladders (pneumatocysts) form at the base of blades of American species, such as "Nereocystis lueteana," (Mert. & Post & Rupr.) to hold the kelp blades close to the surface.