Family: Trichome (filamentous structure) lacks heterocysts; with equal diameter throughout whole length; no hair-like structure; no branching. Genus: A single trichome within a rigid sheath; sheath clear or yellowish; filaments planktonic or agglutinated (Illustrations of The Japanese Fresh-water Algae, 1977).

31 μm 63 μm 94 μm; x 640