Description: Large to 25 cms or more long, filamentous and much-branched.

Habitat: Rock pools in the littoral and in estuaries and lagoons.

Distribution: Widespread from the Shetlands to the Channel Islands in the British Isles. Europe: Mediterranean, Portugal, Atlantic coast of Spain and France, Netherlands, Baltic Sea, Faroes and Iceland. Greenland. Atlantic coast of North America: Canada, Maine, New Hampshire, Massachusetts, Rhode Island, Connecticut, New Jersey and Florida. Further afield: Jamaica, Alaska to San Diego and California, South Africa and Australia.

Similar Species: Most species of Cladophora are similar and difficult to identify.

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

iNaturalist: Cladophora sericea at iNaturalist World Species Observations database.

WoRMS: Cladophora sericea at World Register of Marine Species.