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: Axis-brach differentiation slightly conspicuous; apical cells hairly; cell body cylindrical, slightly swelled at the center forming slight constriction at cell-cell junction; axial cells 20-55 μm long, 10-15 μm in diam., branching cells 12-35 μm long, 8-12 μm in diam.; a single chloroplast plate-like, with one or several pyrenoids (Illustrations of The Japanese Fresh-water Algae, 1977).