Description: Thallus of dense tufts, erect to 3 cms from prostrate axes. Terete and ecorticate with small axial cell and 4 pericentral cells. Rhizoids formed from periaxial cells and remaining in open contact with the pericentral cells. Cystocarps urceolate.

Habitat: Common. Epilithic, epizoic and epilithic in the littoral.

Distribution: Known in the British Isles from the south coasts of England, Wales and in Ireland from Co. Cork to Co. Donegal also Co. Dublin. Europe: Mediterranean, Portugal, Atlantic coasts of Spain and France, Atlantic coast of America: Prince Edward Island to New England, North Carolina, Florida to Brazil. Further afield: Bermuda, Eest Indies, the Canary Islands, Morocco and the Indian Ocean.

Similar Species: Polysiphonia stricta.

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

iNaturalist: Polysiphonia atlantica at iNaturalist World Species Observations database.

WoRMS: Polysiphonia atlantica at World Register of Marine Species.