Section [ Ornatae ]:
Semicells circular, ellipsoid, reniform; cell surface granulated or spiny
(Illustrations of The Japanese Fresh-water Algae, 1977).
Species:
Cosmarium portianum W. Archer var. portianum ?,
cell body 33 μm long, 28 μm wide, isthmus 10 μm wide,
x 400, x 640, rice field, Higashi-sano (near Minami-kamishiro railway station), Hakuba village, Nagano Pref., Japan, October 3, 2004 by Y. Tsukii
31 μm
63 μm
94 μm; x 640