Description: Thallus of uniseriate, unbranched and erect filaments. Growing from a prostrate monostromatic base becoming multiseriate, sometimes as a monostromatic ribbon-like blade to 5 mm long.

Habitat: Uncommon. Epiphytic on Zostera and various algae in the lower littoral or shallow sublittoral.

Distribution: Widespread around the British Isles. Europe: Mediterranean, Portugal, Atlantic coast of Spain and France. Further afield: Pacific coast of America from British Columbia to Peru, South Africa and the Canary Islands.

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

iNaturalist: Porphyrostromium boryanum at iNaturalist World Species Observations database.

WoRMS: Porphyrostromium boryanum at World Register of Marine Species. Accepted name: Porphyrostromium boryanum (Montagne) P.C.Silva, 1996. AphiaID: 145500.

Classification: Biota; Plantae; Biliphyta; Rhodophyta; Proteorhodophytina; Compsopogonophyceae; Erythropeltales; Erythrotrichiaceae; Porphyrostromium