Subgenus: Entomum (Apical area deeply indented or notched) Section: Incisa (Cell surface smooth; apical area without spiny projections) Species: Cell body elongated ellipsoidal, 98-117-(123) μm long, 53-64-(67) μm wide, L/W=2; semicells consisting of five lobes (one terminal, four lateral); bay opening between terminal and anterior lateral lobe is deep and narrow; anterior lateral lobes smaller than posterior one; posterior lobes with slight depressions; terminal lobe laterally extended and apically flattened; semicell with 5 bulges (2 anterior, 3 posterior), 1 pore present between the anterior bulges (Illustrations of The Japanese Fresh-water Algae, 1977).

Similar genus -->> E. affine, E. humerosum, E. pinnatum

31 μm 63 μm 94 μm; x 640

Euastrum affine (Greville) Ralfs var. affine, cell body 147 μm long, 78 μm wide, isthmus 24 μm wide, x 400, x 640, Azami-ike (pond), Norikura highland, Azumi, Matsumoto city (formerly Azumi village), Nagano Pref., Japan, June 8, 2006 by Y. Tsukii

Images of collecting locality: Azami-ike (pond), Norikura highland, Azumi, Matsumoto city (formerly Azumi village), Nagano Pref., Japan, June 8, 2006 by Y. Tsukii