Species: Cell body medium in size, slightly curved, centrally straight, gradually tapered toward ends, both ends truncated with rounded corners, 163-(190-350) μm long, 8-(8.4-13)-20 μm wide, L/W = 25-32; cell wall smooth, bands absent; chloroplasts with 5-7 pyrenoids (Illustrations of The Japanese Fresh-water Algae, 1977).

31 μm 63 μm 94 μm; x 640

Images of collecting locality: No.1, Kashibaru marsh, Karatsu city, Saga Pref., Japan, November 22, 2006 by Y. Tsukii