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,
semicell 57 μm long, 57 μm wide, L/W=, isthmus 18 μm wide,
x 640, No. 9-1, Mida-ga-hara (bog/marsh), Gassan (mountain), Tsuruoka city (formerly Haguro town) & Shonai town (formerly Tachikawa town), Yamagata Pref., Japan, August 3, 2006 by Y. Tsukii
31 μm
63 μm
94 μm; x 640