Species[ var. logiense]: Cell body slightly longer than width, 59-65 μm long, 48-53 μm wide, isthmus 16-22.4 μm wide; semicells reniform, basal corners rounded, with 2 pyrenoids. [f. expansa]: Cell body slightly longer than width, 64.4-67 μm long, 50.4-53 μm wide, isthmus 16.8-18 μm wide; semicells reniform, basal corners rounded, apex broader than that of var. logiense; cell wall covered with many granules (Illustrations of The Japanese Fresh-water Algae, 1977).

31 μm 63 μm 94 μm; x 640

Cosmarium logiense Bisset var. logiense ?, cell body 45 μm long, 42 μm wide, isthmus 16 μm wide, L/W=1.1, x 640, water field near Takao bridge, near Takao-sakura park, Kitamoto city, Saitama Pref., April 17, 2005 by Y. Tsukii
31 μm 63 μm 94 μm; x 640

Cell body 48 μm long, 42 μm wide, isthmus 17 μm wide, L/W=1.1, x 640

Cell body 50 μm long, 42 μm wide, isthmus 17 μm wide, L/W=1.2, x 640