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).
Micrasterias thomasiana Archer var. pulcherrima W. et G.S. West,
cell body about 220 μm long, 185 μm wide, L/W=1.2,
x 200, x 400, x 640, Kakuman-buchi at Akagi mountain, Fujimi village, Gunma Pref., Japan, April 30, 2005 by Y. Tsukii
150 μm; x 400 :
94 μm; x 640