Genus: Colonies of 4 (or 2, 8, 16) cells attached side by side, arranged linearly or zigzag; cell body elliptical or spindle or crescent in shape; terminal cells with spiny projections in many species; cell wall usually smooth, but in some species granulated or dented or ridged (Illustrations of The Japanese Fresh-water Algae, 1977).
Species: Colonies of 4 cells, arranging learly; cell body spindle-shaped, both ends slightly pointed, 10-22 μm long, 5-8 μm wide; each cell with longitudinal ridges on both sides (Illustrations of The Japanese Fresh-water Algae, 1977).
S. acutiformis 14 x 4.5 μm Sagiyama Memorial P. Saitama, 2002 |
S. acutiformis var. bicaudatus ? μm Numappara marsh Kuroiso Tochigi, 2003 |
S. acutiformis 12-14 x 4.5 μm Iruma river Kawagoe Saitama, 2004 |
