Description: Erect, usually uniseriate filaments to 25 cms long, tufted and richly branched, usually opposite.

Habitat: Common. Occurs from high intertidal to 10 m sublittoral; often epiphytic on Fucus.

Distribution: Widespread in the British Isles from the Shetlands to the Channel Islands. Europe: Portugal, Spain, France, Netherlands, Baltic Sea, Norway, Faroes, Jan Mayen and Bjornoya and Iceland. Greenland. Atlantic coast of North America: Canada, Maine, New Hampshire, Massachusetts, Rhode Island, Connecticut and Long Island, New Jersey, Delaware, Maryland and Virginia. Further afield: Arctic Seas from Spitzbergen to Murman Sea, Novaya Zemlya, Kara Sea and Siberian Sea to the west coast of Greenland, Bearing Sea, Alaska, California, Japan, Angola and Mauritania.

Similar Species: Many fine filamentous brown algae are similar, microscopic examination is required for identification.

Distribution Map from NBN: Pylaiella littoralis at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Pylaiella littoralis at iNaturalist World Species Observations database.

WoRMS: Pylaiella littoralis at World Register of Marine Species.