Genus: Unicellular; variable in shape; a constriction at the center of the cell body; mostly longer than wide; flattened; each semicell hemispherical, spherical, ellipsoidal, rectangular, pyramidal or kidney-shaped; no apical indentation
Subgenus [Eucosmarium]: Cell body dorso-ventrally compressed, with strong constriction at the center, transverse section elliptical or diamond-shaped.
Section [Quadratiformes]: Cell surface smooth; semicells rectangular (Illustrations of The Japanese Fresh-water Algae, 1977).
Species:
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C. rectangulare 41 x 31 μm near City Hall Fujimi Saitama, 2004 |
C. rectangulare 40 x 30 μm Konuma Sakado Saitama, 2004 |
C. rectangulare 37 x 30 μm 42 x 31 μm rice field Ichinoseki Iwate, 2005 |
C. rectangulare 36 x 29 μm Univ. A.V.M. Obihiro Hokkaido, 2005 |