Genus: cell body flat, constricted at the center; semicell ellipsoidal or subtriangular, central area of the apex slightly elevated,
cells connected with each other at their central area of apex forming filament.
Species: Filaments not twisted; cells loosely connected to be separated; cell body 8.4-11 μm long, 7-10.8 μm wide, constriction 4-6 μm wide; semicells broad hexagonal in shape, apex slightly depressed, with two short projections to connect with adjacent cells (Illustrations of The Japanese Fresh-water Algae, 1977).
Images of collecting locality:
Azami-ike (pond), Norikura highland, Azumi, Matsumoto city (formerly Azumi village), Nagano Pref., Japan, June 8, 2006 by Y. Tsukii