Description: Thallus of microscopic uniseriate filaments growing endophytically. Filaments irregularly branched and radiating from a centre, cells with or without hairs.

Habitat: Endophytic in Chondrus crispus also in shells of the low and sublittoral.

Distribution: Generally around the British Isles including the Shetlands, probably under-recorded. Europe: Mediterranean, Azores, Portugal, Spain, France, Netherlands, Baltic Sea and Norway. Greenland. Atlantic coast of North America: Canada, Maine, New Hampshire, Massachusetts, Connecticut and Long Island, New Jersey, Virginia, North Carolina and Florida. Further afield: Bermuda, British Columbia, California, Galapagos Islands and New Zealand.

Similar Species: Microscopic examination required for identification.

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

iNaturalist: Entocladia viridis at iNaturalist World Species Observations database.

WoRMS: Entocladia viridis at World Register of Marine Species.