Genus: Trichome without mucous sheath; straight, long, consisting of numerous cells (Illustrations of The Japanese Fresh-water Algae, 1977). Species (var. crasa): Trichome straight or slightly curved, no constriction at cell-cell junction, 1.5-2 μm in diam.; cell body about 4-10 times longer than its width; septum indisinguishable (provably near pseudovacuoles) (Illustrations of the Japanese Fresh-water Algae, 1977).

31 μm 63 μm 94 μm; x 640

Images of collecting locality: Drainage ditch, Kami-omino, Kawajima (Kawashima) town, Saitama Pref., February 25, 2006 by Y. Tsukii