Description: Thallus erect to 13 cms long, terete with 4 pericentral cells and cortication developing on the older parts. Branches pseudodichotomously.

Habitat: Rare. Epiphytic, epilithic and on artifical surfaces from low littoral to 13 m in the sublittoral. Cystocarps globose.

Distribution: Widespread in the British Isles. Europe: Mediterranean and France.

Similar Species: Polysiphonia elongata is similar but shows cortication is more developed and the branches are attenuate at their base.

Key Identification Features:

• 4 pericentral cells, cortication in the older parts.

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

iNaturalist: Polysiphonia elongella at iNaturalist World Species Observations database.

WoRMS: Polysiphonia elongella at World Register of Marine Species.