Section [ Actinotaenium ]: Cell body cylindrical, slightly constricted at the center, cell surface smooth or dotted or punctated (Illustrations of The Japanese Fresh-water Algae, 1977). Species: Cell body small, 22-(32-43)-60 μm long, 10.5-(20-23)-32 μm wide, isthmus 9.5-(18-21.5)-30 μm wide, L/W=2; semicells ovoidal; (Illustrations of the Japanese Fresh-water Algae, 1977).

31 μm 63 μm 94 μm; x 640

A parasitic fungus ? infecting Cosmarium curtum (Brébisson) Ralfs ??, x 640, Fukasaku-gawa Yusuichi, Saitama city, Saitama Pref., Japan, May 2002 by Y. Tsukii
31 μm 63 μm 94 μm; x 640

Cosmarium curtum (Brébisson) Ralfs: Cell body small, 22-(32-43)-60 μm long, 10.5-(20-23)-32 μm wide, isthmus 9.5-(18-21.5)-30 μm wide, L/W=2; semicells ovoidal; (Illustrations of the Japanese Fresh-water Algae, 1977).