Genus: Trichome without mucous sheath; straight, long, consisting of numerous cells.
Species: Trichome pale bluegreen, septum not constricted, gradually attenuated toward curved ends, 3-3.5 μm wide, slightly elongate or nearly the same as its width; cell body containing granules (Illustrations of The Japanese Fresh-water Algae, 1977).
O. uncinata ?
x 4 μm
L/W=
Hakama marsh
Madarao highland
Niigata, 2005
O. uncinata ?
5 x 3 μm
L/W=1.7
Yoshigadaira m.
Shirane mountain
Gunma, 2005
O. uncinata ?
3-5 x 3 μm
L/W=1-1.7
Suiren-numa
Hakkoda mountain
Aomori, 2005
