Subgenus [Eucosmarium]:
Cell body dorso-ventrally compressed, with strong constriction at the center,
transverse section elliptical or diamond-shaped.
Section [ Cyclidium ]:
Cell surface smooth; semicells half circle, half ellipsoid
(Illustrations of The Japanese Fresh-water Algae, 1977).
Species[ magnum ]:
(Illustrations of The Japanese Fresh-water Algae, 1977).
Cosmarium pseudopyramidatum Lundell var. pseudopyramidatum,
cell body μm long, μm wide, L/W=, isthmus μm wide,
x 640, No.5, Omine-numa (pond/marsh), Omine, Minakami town (formerly Tsukiyono town), Gunma Pref., Japan, October 21, 2007 by Y. Tsukii 31 μm
63 μm
94 μm; x 640
Images of collecting locality:
No.5, Omine-numa (pond/marsh), Omine, Minakami town (formerly Tsukiyono town), Gunma Pref., Japan, October 21, 2007 by Y. Tsukii