Subgenus: Entomum (Apical area deeply indented or notched)
Section: Incisa (Cell surface smooth; apical area without spiny projections)
Species:
(Illustrations of The Japanese Fresh-water Algae, 1977).
Euastrum pinnatum Ralfs,
cell body (semicell) 60 μm long, 62 μm wide, L/W=, isthmus 16? μm wide,
x 640, Tashirodaira marsh, Hakkoda mountain, Aomori city, Aomori Pref., Japan, July 17, 2005 by Y. Tsukii
31 μm
63 μm
94 μm; x 640