Description: Thallus very fine. At first a hollow ball but splits to form a monostromatic blade 45 mm long and 40 mm wide.

Habitat: Epiphytic on other algae particularly Desmarestia aculeata in the lower littoral and sublittoral to 20 m.

Distribution: England: Cornwall. Ireland: Cos Cork, Mayo, Galway, Down and Antrim. Scotland: Shetlands. Europe: Atlantic coast of Portugal, Spain, France, Baltic, Faroes, Norway, Spitzbergen and Iceland. Greenland. Atlantic coast of North America: Canada, New Hampshire, Connecticut and Long Island and North Carolina.

Key Identification Features:

• Very small monostromatic blade.

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

iNaturalist: Porphyropsis coccinea at iNaturalist World Species Observations database.

WoRMS: Porphyropsis coccinea at World Register of Marine Species.