Sargassum johnsonii Sargassum johnsonii Sargassum johnsonii Chapman, 1961, is a brown seaweed of the genus "Sargassum" that is endemic to the Three Kings Islands in New Zealand. It is sometimes called totara weed because of the resemblance to the foliage of the NZ native tree totara. Its scientific name derives from its discoverer, Magnus Earle Johnson, Three Kings Islands explorer and captain of the yacht "Rosemary", who landed botanists on the islands on several occasions. "Sargassum johnsonii" grows in rocky intertidal habitats, often extending to the subtidal zone up to a depth of 40 m. It is a foundation species, and being
Sargassum color and consist of a holdfast, a stipe, and a frond. Oogonia and antheridia occur in conceptacles embedded in receptacles on special branches. Some species have berrylike gas-filled bladders that help the fronds float to promote photosynthesis. Many have a rough, sticky texture that, along with a robust but flexible body, helps it withstand strong water currents. Large, pelagic mats of "Sargassum" in the Sargasso Sea act as one of the only habitats available for ecosystem development; this is because the Sargasso Sea lacks any land boundaries . The Sargassum patches act as a refuge for many species in different