Description: Monosiphonous filaments creeping endophytically in Porphyra, forming brown patches on species of Porphyra.

Habitat: Rare, epiphytic in species of Porphyta.

Distribution: Recorded from scattered sites on coasts of British Isles. Europe: Spain, France, Baltic Sea, Norway and Iceland. Atlantic coast of North America: Canada, New Hampshire and Massachusetts.

Similar Species: Mikrosyphar polysiphoniae is endophytic in Porphyra.

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

iNaturalist: Mikrosyphar porphyrae at iNaturalist World Species Observations database.

WoRMS: Mikrosyphar porphyrae at World Register of Marine Species. Accepted name: Mikrosyphar porphyrae Kuckuck, 1897. AphiaID: 145448.

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