Description: Variable. Terete with branching usually opposite and narrow at junction with main filament which may be tubular. To 30 cms long the branches ending in colourless hairs. Sporangia in patches or whorls appearing as rings round the thallus.

Habitat: Epiphytic in the low littoral and shallow sublittoral.

Distribution: Generally of western distribution in the British Isles from Ireland, south-west Wales and western Scotland including the Shetlands. Europe: Mediterranean, Atlantic coasts of Spain and France, Netherlands, Baltic Sea and Norway. Atlantic coast of North America: Canada, Massachusetts, Rhode Island, Connecticut and Virginia.

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

iNaturalist: Striaria attenuata at iNaturalist World Species Observations database.

WoRMS: Striaria attenuata at World Register of Marine Species. Accepted name: Striaria attenuata (Greville) Greville, 1828. AphiaID: 548021.

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