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 muticum observed in temperate environments. "Sargassum muticum" grows from half-tide to infralittoral areas (to a depth of 10 m.). It is fixed on solid substrates like rocks, stones, shells. It is highly tolerant towards temperature and salinity variations. The optimal temperature is between 17 and 20 °C but it tolerates -9 and 30 °C. Originally from Japan, it is thought to have gained worldwide distribution through being transported with Japanese oysters ("Crassostrea gigas"). "Sargassum muticum" was introduced to the Californian coast in the 40's and in Europe in the 70's (The species was first found in the British Isles in the