Genus: Filamentous algae without branching, no rhizoids, covered with gelatinous sheath; cell body cylindrical or ellipsoidal, cells attached side by side or separated; a single chloroplast band-form, with a pyrenoid (Guide book to the "Photomicrographs of the Freshwater Algae", 1998). Species: Filament covered with a thick gelatinous coat; 2 or 4 cells closely contacted; cell body elongated ellipsoid or ovoid, 4-6 μm long, 7-9 μm wide; chloroplasts parietal, with a single pyrenoid (Photomicrographs of the Freshwater Algae, vol.4, 1985).

31 μm 63 μm 94 μm; x 640

Geminella ellipsoidea (Prescott) Smith var. ellipsoidea (or Ulothrix ?), cell body 7-12 μm long, 12 μm wide, gelatinous sheath 3 μm in thickness, x 100, x 200, x 400, x 640, Karakemi marsh, Yasaka, Omachi city (formerly Yasaka village), Nagano Pref., Japan, May 8, 2006 by Y. Tsukii
31 μm 63 μm 94 μm; x 640

Images of collecting locality: Karakemi marsh, Yasaka, Omachi city (formerly Yasaka village), Nagano Pref., Japan, May 8, 2006 by Y. Tsukii