Description: Thallus foliose and monostromatic, attached by minute holdfast. Thin semi-transparent blade to 22 cms, or more, long and 20 cms broad.

Habitat: Common. Epiphytic on other algae, also on shells, pebbles of the lower littoral and the shallow sublittoral.

Distribution: Widespread throughout the British Isles. Europe: Mediterranean, Portugal, Spain, France, Netherlands, Baltic, Norway, the Faroes and Iceland. Atlantic coast of North America: Canada, Maine, New Hampshire, Massachusetts, Rhode Island, Connecticut and Long Island, New Jersey, Virginia and N.Carolina. Further afield: the Canary Islands.

Similar Species: Other species of Porphyra.

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

iNaturalist: Porphyra leucosticta at iNaturalist World Species Observations database.

WoRMS: Porphyra leucosticta at World Register of Marine Species.