Species:

Note: The species forms dark red and more than 0.5 mm thick mucilaginous patches on the substratum. It is composed of prostrate filaments loosely united by mucilage. The cells of the filaments are long and barrel-shaped in the lowermost part, 12-14 micrometers in diameter, tapering to more parallel-sided cells, 6-11 micrometers in diameter, in the apical part. The species is most common in the sublittoral zone. It has zonately arranged tetraspores. The species can be confused with the ‘Petrocelis’-stage of Mastocarpus stellatus (in shallow subtidal) and Haemescharia hennedyi, but none of these have zonate tetrasporangia.