Description: Thallus monosiphonous with whorls of 2 or 3 to 4 branches per axial cell, erect tufts to 15 cms long. Branchlets in pairs, distichous, or with 3 to 4 paired branches at right angles to the other pair.

Habitat: Common on a variety of surfaces in pools of the low littoral and sublittoral to 20 m.

Distribution: Generally distributed around the British Isles including the Shetlands. Europe: Portugal, Baltic and the Netherlands. Further afield: Canary Islands.

Similar Species: Pterothamnion crispum.

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

iNaturalist: Pterothamnion plumula at iNaturalist World Species Observations database.

WoRMS: Pterothamnion plumula at World Register of Marine Species. Accepted name: Pterothamnion plumula (J.Ellis) Nägeli, 1855. AphiaID: 144683.

Classification: Biota; Plantae; Biliphyta; Rhodophyta; Eurhodophytina; Florideophyceae; Rhodymeniophycidae; Ceramiales; Ceramiaceae; Ceramioideae; Pterothamnieae; Pterothamnion