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: Cell body small, ovoid in shape, 5-7 μm long, 2-3 μm wide; spiny projections short (1.5-3 μm long) (Illustrations of The Japanese Fresh-water Algae, 1977).

50 μm 100 μm 150 μm; x 400

Scenedesmus abundans ?, x 400, 1998 by Y. Tsukii

S. abundans (Kirchner) Chodat var. abundans (Syn.: S. caudatus Corda f. abundans Kirchner; S. quadricauda (Turpin) Brébisson var. abundans Lagerheim): Clonies of 4 cells arranged linearly; cells at both ends have several spiny projections, 6-8 μm at both termini and 3-5 μm at sidewall; cell body ovoid or ellipsoid 9-20 μm long, 3-5 μm diam. (Illustrations of The Japanese Fresh-water Algae, 1977).

S. abundans var. longicauda G. M. Smith: Spiny projections longer than those of var. abundans, 10-12 μm at both termini and 5-7 μm at sidewall; cell body 8-10 μm long, 3-4 μm diam. (Illustrations of The Japanese Fresh-water Algae, 1977).

S. abundans var. spicatus (W. et G. S. West) G. M. Smith: Spiny projections more in numbers and smaller (1.5-3 μm) than those of var. abundans, cell body 7-10 μm long, 3-4 μm diam. (Illustrations of The Japanese Fresh-water Algae, 1977).

* S. abundans var. brevicauda G. M. Smith: Spiny projections smaller (1.5-3 μm) than those of var. abundans, cell body 5-7 μm long, 2-3 μm diam. (Illustrations of The Japanese Fresh-water Algae, 1977).