Species [ var. turgidus ]: Cells bright blue-green, sometimes coarsely granulated, 8-32 μm in diam. (without sheath), sheaths 2-6 μm in thickness (Photomicrographs of the Freshwater Algae, vol. 3, 1985). Colony of 2-4 cells, covered with layered gelatinous sheath; cell body 8-32 μm in diam. (excluding sheath), 13-40 μm in diam. (including sheath). [ var. maximus ]: Cell body 22-45 μm in diam. (excluding sheath, 5-10 μm in thickness) [ var. thermalis]: Sheath present, but not layered (Illustrations of The Japanese Fresh-water Algae, 1977).

31 μm 63 μm 94 μm; x 640