Description: Thallus small tubular when young, becomes compressed when older, to 5 cms (or more) long and 4 mm wide in dense tufts. Finely branched.

Habitat: Epilithic in the upper littoral and supralittoral zones, also in brackish water.

Distribution: All around the coasts of the British Isles. Europe: Mediterranean, Portugal, France, Netherlands, Baltic, Norway, Spitzbergen and Iceland. Greenland. Atlantic coast of North America: Canada, Maine, New Hampshire, Massachusetts, Rhode Island, Connecticut, New Jersey, Delaware, Maryland and Virginia. Further afield: Canary Islands, Bermuda, Japan, southern Australia, New Zealand and South Africa.

Similar Species: Enteromorpha, but microscopically distinctive; other species of Blidingia.

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

iNaturalist: Blidingia marginata at iNaturalist World Species Observations database.

WoRMS: Blidingia marginata at World Register of Marine Species.