Genus: Filamentous algae, axis-branch differentiation incomplete; terminal cells tapered to form spiny projections; branches do not form in tuft (Illustrations of The Japanese Fresh-water Algae, 1977). Species: Branching not so frequent; secondary branching rare; branching axial cells shorter compared to non-branching cells; axial cells up to 8-12-(15) μm in diam., L/W=2-4; constriction present at cell junction (Illustration of the Japanese fresh-water algae, 1977).

50 μm 100 μm 150 μm; x 400 : 31 μm 63 μm 94 μm; x 640