Description: Thallus erect to 60 cms or more growing from a small discoid holdfast. Main axis with numerous irregular branching, often bushy.

Habitat: Common, epilithic or epiphytic in the lower littoral.

Distribution: Widespread around the British Isles except the east coast of England. Europe: France, Baltic Sea, Norway, Faroes and Iceland. Atlantic coast of North America: Canada, Maine, New Hampshire, Massachusetts, Rhode Island, Connecticut, Long Island, New Jersey and Virginia. Further afield: Arctic Seas: Spitzbergen, Murman Sea, White Sea , Cumberland Sound in and the west coast of Greenland in Baffin Bay.

Similar Species: Desmarestia viridis, in a denuded state, is similar however it has regularly opposite branches.

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

iNaturalist: Dictyosiphon foeniculaceus at iNaturalist World Species Observations database.

WoRMS: Dictyosiphon foeniculaceus at World Register of Marine Species.