Sargassum muticum Sargassum muticum Sargassum muticum, commonly known as Japanese wireweed, is a large brown seaweed of the genus "Sargassum". It is an invasive seaweed with high growth rate (up to 10 cm per day during spring). It has an efficient dispersion thanks to its floats. "Sargassum muticum" is a brown seaweed, normally brown to yellowish with a length up to 10 m. It is an autotroph that uses energy from sunlight. The photosynthesis is facilitated thanks to aerial vesicles which allows the algae to raise to the surface. "Sargassum muticum" is composed of two distinct parts: a perennial part, which contains
Sargassum muticum Isle of Wight in 1973). Currently, the alga is widespreaded from Norway to Portugal along Atlantic's coasts. "Sargassum muticum" has a range stretching from Campbell river, British Columbia to Baja in California. In Europe it extends along the coasts of Great Britain, France, Scandinavia, Baltic Sea, Helgoland, Netherlands, Ireland, the Iberian Peninsula and into the Mediterranean from Italy and the Adriatic. It is recorded from Japan, China and Alaska. Recently, some specimens were found on Moroccan coasts. It illustrates its huge tolerance regarding to its environments. Herbarium specimens are now stored in the Ulster Museum (BEL catalogue numbers: F11241 -