Description: Thallus of dense erect tufts to 5 cms long. Mucilaginous. Branching irregularly alternate. Axial cells bearing whorls of ramuli in threes deviding to form branchlets.

Habitat: Epiphytic in the mid to lower littoral and to 8 m sublittorally.

Distribution: Very local in distribution. Southern coasts of the British Isles: Devon, Cornwall, Wexford, Cork and the Channel Islands. A record from Cardigan Bay may be the northermost record. Europe: Mediterranean, Azores, Portugal and Atlantic coast of Spain. Further afield: Canary Islands, Florida, Bermuda, Bahamas, Barbados, West Indies and South Africa.

Similar Species: Schmitzia neapolitana; Platoma bairdii; Calosiphonia vermicularis; Dudresnaya verticillata.

Key Identification Features:

• Always epiphytic. Whorls of branches in threes.

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

iNaturalist: Crouania attenuata at iNaturalist World Species Observations database.

WoRMS: Crouania attenuata at World Register of Marine Species.