Description: Tiny parasitic alga on Polysiphonia lanosa. Grows cushon-like to about 1 mm in diameter.

Habitat: Parasitic on Polysiphonia lanosa which itself is epiphytic, almost exclusively, on Ascophyllum nodosum. As A. lanosa is normally found on more sheltered shores this species is to be found there also.

Distribution: British Isles including the Shetlands. Europe: Spain, France, Netherlands and the Faroes. Atlantic coast of North America: Canada, Maine, New Hampshire, Massachusetts, Rhode Island, Long Island and Mexico. Further afield: north Russia and Pacific America.

Similar Species: Harveyella mirabilis however this is parasitic on Rhodomela confervoides.

Key Identification Features:

• Minute parasite on Polysiphonia lanosa.

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

iNaturalist: Choreocolax polysiphoniae at iNaturalist World Species Observations database.

WoRMS: Choreocolax polysiphoniae at World Register of Marine Species. Accepted name: Choreocolax polysiphoniae Reinsch, 1875. AphiaID: 145609.

Classification: Biota; Plantae; Biliphyta; Rhodophyta; Eurhodophytina; Florideophyceae; Rhodymeniophycidae; Ceramiales; Rhodomelaceae; Rhodomeleae; Choreocolax