Description: Thallus forming small spots up to 1 mm in diameter. At the periphery monostromatic branched filaments radiate out, in the centre the cells form small erect filaments to 9 cells long usually unbranched but with lateral protuberances, closely packed and turf-like.

Habitat: Common. Epiphytic especially on Ulva and Enteromorpha in the low littoral.

Distribution: Widely distributed in the British Isles. Europe: Azores, Mediterranean and the Black Sea, Portugal, Atlantic coasts of Spain and France, Netherlands, Denmark, Baltic Sea, Sweden, Norway, Faroes and Iceland. Greenland. Atlantic coast of North America: Canada, Maine, New Hampshire, Massachusetts, Rhode Island, Connecticut, New Jersey and Virginia. Further afield: Baffin Bay in the Arctic Sea, Caribbran, Atlantic and Pacific South America, the Canary Islands. Pacific coast: Alaska to California. Australia and New Zealand.

Similar Species: There are a number of similar species growing as epiphytes or epilithic - all very small and difficult to identify. Microscopic examination is required.

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

iNaturalist: Myrionema strangulans at iNaturalist World Species Observations database.

WoRMS: Myrionema strangulans at World Register of Marine Species. Accepted name: Myrionema strangulans Greville, 1827. AphiaID: 144985.

Classification: Biota; Chromista; Harosa; Heterokonta; Ochrophyta; Phaeophyceae; Fucophycidae; Ectocarpales; Chordariaceae; Myrionema