Description: Tufts of monosiphonous erect filaments to 30 mm long with difuse branching.

Habitat: Rare. Epiphytic on Fucus and other algae.

Distribution: Recorded from a few scattered sites in Britain. Europe: Portugal, Spain, France, Netherlands, Norway and Spitzbergen. Atlantic coast of North America: Canada. Furrther afield: Jamaica, the Canary Islands, South Africa and California.

Similar Species: Many fine filamentous brown algae are similar and require microscopic examination for identification.

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

iNaturalist: Feldmannia irregularis at iNaturalist World Species Observations database.

WoRMS: Feldmannia irregularis at World Register of Marine Species. Accepted name: Feldmannia irregularis (Kützing) Hamel, 1939. AphiaID: 145415.

Classification: Biota; Chromista; Harosa; Heterokonta; Ochrophyta; Phaeophyceae; Fucophycidae; Ectocarpales; Acinetosporaceae; Feldmannia