Species: Cell body fusiform or elongated ovoid, 20-53 μm long, tapered at both ends, cell wall thin, chloroplasts plate-like, with two large pyrenoids one located at anterior half and another at posterior half, stigma ovoid or pear-shaped, located at anterior 1/4-1/3 of the cell body, many contractile vacuoles (An Illustrated Guide to Freshwater Zooplankton in Japan, 2000). Cell body fusiform to spindle-shaped, 20-80(-120) μm long, 4-10(-12) μm wide; stigma longitudinally elongated elliptical, located close to tapering anterior end; [var. truncatum Skuja 1956]: 20-35 μm long, 3-5 μm wide; [var. opulentum Ettl 1960]: 120-155 μm long, 10-12 μm wide; [var. gigas Hortobagyi 1979]: 100-110 μm long, 15-17 μm wide; (Süßwasserflora von Mitteleuropa 9, Chlorophyta I, 1983). Cell body spindle-shaped, 23-50 μm long, 4-9 μm wide (Illustrations of The Japanese Fresh-water Algae, 1977).

31 μm 63 μm 94 μm; x 640

Chlorogonium elongatum (Dangeard) Dangeard, stock Sssm-5, identified by T. Nakada, axenic culture, bar represents 5 μm, x 640, rice field, Shimo-muneoka, Shiki city, Saitama Pref., Japan, October 24, 2004 collected by Y. Tsukii, photo by T. Nakada