Description: Thallus erect, ecorticate and branching in one plane to 7 cms long. All branches regularly alternate. Tetrasporangia pedicellate or terminal.

Habitat: Widely distributed but a rather uncommon species. Mainly sublittoral.

Distribution: Widely distributed around the British Isles except the north-east of England and east of Scotland, particularly well recorded on the north-east of Ireland and the west coast of Scotland including the Shetlands. Europe: Mediterranean and Portugal. Further afield: Canary Isles.

Similar Species: Some species of Aglaothamnion and Compsothamnion gracillimum.

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

iNaturalist: Compsothamnion thuyoides at iNaturalist World Species Observations database.

WoRMS: Compsothamnion thuyoides at World Register of Marine Species. Accepted name: Compsothamnion thuioides (Smith) F.Schmitz, 1889. AphiaID: 144573.

Classification: Biota; Plantae; Biliphyta; Rhodophyta; Eurhodophytina; Florideophyceae; Rhodymeniophycidae; Ceramiales; Ceramiaceae; Compsothamnioideae; Compsothamnieae; Compsothamnion