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 109 μm long, 98 μm wide, L/W=1.1, isthmus 20 μm wide,
x 640, Mida-ga-hara (bog), Gassan (mountain), Haguro & Tachikawa town, Yamagata Pref., Japan, July 10, 2005 by Y. Tsukii
31 μm
63 μm
94 μm; x 640
Cell body 111 μm long, 105 μm wide, L/W=1.1, isthmus 21 μm wide, x 640