Species: Cell body medium in size, body length about 4/3 longer than its width, (67-76)-90-105 μm long, (50-62)-75-90 μm wide, isthmus (49-56)-79 μm wide; semicell half-circle in shape, apex slightly fattened; cell body covered with minute granules but smooth at the constriction zone; apical view of the cell body broad ellipsoidal (Illustrations of the Japanese fresh-water algae, 1977). I/W (isthmus/width) =0.88
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Similar species -- >> C. connatum (62-100 x 45-74, isthmus 37-53 μ, I/W=0.72);
C. alpestre
72 x 56 μm
Kodanuki marsh
Fujinomiya
Shizuoka, 2005
C. alpestre
70 x μm
Numappara marsh
Kuroiso
Tochigi, 2003
C. alpestre
72,77 x μm
Numappara marsh
Kuroiso
Tochigi, 2007
C. alpestre
70 x 52 μm
O-ike park
Yabuki
Fukushima, 2003
C. alpestre
stock Sku-1
51-54 x 45 μm
I/W=0.96
Kurihashi
Saitama, 2001
C. alpestre
stock ???
66 x 48 μm
I/W=0.93
Numappara marsh
Kuroiso
Tochigi, 2004
C. alpestre
μm
Kashibaru m.II
Karatsu
Saga, 2008
C. alpestre
or C. connatum ?
53 x 39 μm
I/W=0.95
Uruguay, 1999
C. alpestre ?
34 x 29 μm
Uruguay, 1999