Description: Main axis with transverse and longitudinal divisions ending with a large apical cell. In dense tufts less than 1 cm tall with creeping filaments

Habitat: Rare. Growing as tufts or mats in the littoral.

Distribution: Few records from the British Isles. Europe: Portugal, Atlantic coasts of Spain and France, Netherlands, Baltic Sea, Norway, Faroes. Atlantic coast of North America: Canada, Connecticut, Long Island and Virginia. Further afield: Canary Islands, Jamaica. Pacific: Alaska and west coast of America south to Chile, Japan and Australia.

Similar Species: Most species of Sphacelaria, and other small branched brown algae, are very alike and require microscopic examination for identification.

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

iNaturalist: Sphacelaria rigidula at iNaturalist World Species Observations database.

WoRMS: Sphacelaria rigidula at World Register of Marine Species. Accepted name: Sphacelaria rigidula Kützing, 1843. AphiaID: 145902.

Classification: Biota; Chromista; Harosa; Heterokonta; Ochrophyta; Phaeophyceae; Dictyotophycidae; Sphacelariales; Sphacelariaceae; Sphacelaria