Species [ var. obsoletum]:
Cell body medium in size, broad elliptical (wider than length), 34-(39-50) μm long,
42-(48-53)-54 μm wide, isthmus 15.5-(21-25) μm wide;
semicells semielliptical or depressed semicircular, cell wall at basal corner thickened like a papillae;
cell wall punctated and dotted.
[ var. sitvense ]: Cell body relatively large in size, 57-(69-78) μm long, 67-(69-78) μm wide, isthmus 30-(39-42) μm wide (Illustrations of The Japanese Fresh-water Algae, 1977).
Images of collecting locality:
Yukawa-numa (pond), Nishiwaga-machi (town), Iwate Pref., Japan, July 28, 2007 by Y. Tsukii