Section [Margaritiferae]:
Cell surface granulated, gnarled or spiny; semicells pyramidal with flattened apex or trapezoid
(Illustrations of The Japanese Fresh-water Algae, 1977).
Species [var. subcostatum]: Cell body 26-38 μm long, 23-32 μm wide, isthmus 6.5-12 μm. [f. minor W. et G.S. West]: Cell body 19-26 μm long, 18-23 μm wide, isthmus 4.5-9 μm. |
31 μm
63 μm
94 μm; x 640
