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: with arm-like projections (Illustrations of The Japanese Fresh-water Algae, 1977) Species [var. iotanum]: Cell body with 3 arm-like projections, 11 μm long (excluding arms), 18-22 μm long (including arms), 9.8 μm wide (excluding arms), 18-22 μm wide (including arms), isthmus 4-5 μm wide (Illustrations of The Japanese Fresh-water Algae, 1977)

31 μm 63 μm 94 μm; x 640

Staurastrum iotanum Wolle var. iotanum, cell body 24 μm long, 24 μm wide, L/W=1.0 (including arms), isthmus 6 μm wide, x 640, Kumakubo, Nasu-shiobara city (formerly Kuroiso city), Tochigi Pref., Japan, December, 2005, collected by Eizaburo Tsukii, photo by Y. Tsukii
31 μm 63 μm 94 μm; x 640