Genus: Cell body short, radiate in shape; apical view of the cell, triangular, polygonal, ellipsoidal or spindle-shaped; zygospores formed outside of mother cells (Illustrations of The Japanese Fresh-water Algae, 1977) Subgenus: lacks arm-like projections (Illustrations of The Japanese Fresh-water Algae, 1977) Section [Raphidiastrum]: Species:

50 μm 100 μm 150 μm; x 400 : 31 μm 63 μm 94 μm; x 640