Description: Thallus forming small spots up to 1 mm in diameter. At the periphery monostromatic branches radiate out, in the centre the cells form short erect filaments to 12 cells long and lateral protuberances, closely packed and turf-like.

Habitat: Rare. Epiphytic on Laminaria saccharina in the lower littoral and sublittoral to 5 m

Distribution: Few records from the British Isles: Dorset, Cornwall and Shetlands. Probably under-recorded. Europe: Spain, France and the Baltic Sea.

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 papillosum at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Myrionema papillosum at iNaturalist World Species Observations database.

WoRMS: Myrionema papillosum at World Register of Marine Species.