Description: Thallus filamentous, densely but irregularly branched. Cushion-like turfs with rhizoids wrapping around other filament, loose-lying or attached to rock.

Habitat: A shade-loving species found in sheltered places in the littoral, may be found in estuaries.

Distribution: Rare in the British Isles, mainly in the south also the Channel Isles and the south of Ireland. Europe: Mediterranean, Portugal, Atlantic coasts of Spain and France. Atlantic coast of North America: Florida. Further afield: Canary Islands, Caribbean, Jamaica, Kenya, Indian Ocean, Ghana, Cameroon, Solomon Islands and Australia.

Similar Species: Most species of Cladophora are similar and difficult to identify, may be under-recorded.

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

iNaturalist: Cladophora coelothrix at iNaturalist World Species Observations database.

WoRMS: Cladophora coelothrix at World Register of Marine Species.