Description: Growing as small felt-like mats of interlacing branches.

Habitat: Rare, On the walls of caves and overhanging rocks in the littoral.

Distribution: Widely distributed in the British Isles. Europe: France, Netherlands, Baltic Sea, Norway, Faroes and Iceland. West coast of Greenland in the Baffin Bay. Atlantic coast of North America: Virginia.

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

iNaturalist: Sphacelaria nana at iNaturalist World Species Observations database.

WoRMS: Sphacelaria nana at World Register of Marine Species.