Genus:
Cell body flat, large, variable in shape, longer than wide; strong constriction at center;
each semicell with several notches; cell wall with many short spines
(Illustrations of The Japanese Fresh-water Algae, 1977).
Species:
Micrasterias truncata (Corda) Brébisson var. truncata,
cell body 110 μm long, 100 μm wide, L/W=1.1, isthmus 18 ? μm wide,
x 640, Hyoutan-ike (gourd pond), Shiga highland, Yamanouchi town, Nagano Pref., Japan, June 19, 2005 by Y. Tsukii
31 μm
63 μm
94 μm; x 640