Species [ var. angulosum ]: Cell body small, 14-31 μm long, 12.6-21 μm wide, L/W=1.5, isthmus 3.4-6 μm wide; semicells quadrate or hexagonal in shape.
[ var. concinnum ]: Smaller than var. angulosum, (11-12)-13 μm long, 8-12 μm wide, L/W=1.3, isthmus 2.6-4.5 μm wide (Illustrations of the Fresh-water Algae, 1977).
Google Image Search
Similar species -- >> C. rectangulare; C. sexaugulare;
C. angulosum ?
40 x 28 μm
Saitama, 1999
C. angulosum
or C. rectangulare ?
37 x 28 μm
Ishinazaka
Furukawa
Miyagi, 2003
C. angulosum ?
26 x 14 μm
Ibaraki, 2000
C. angulosum
v. angulosum
20 x 17 μm
22 x 18 μm
rice field
Ichinoseki
Iwate, 2005
C. angulosum
v. angulosum
17 x 13 μm
Saitama, 1999
C. angulosum
v. angulosum
14 x 11 μm
Chiba-Minato Park
Chiba, 2003
C. angulosum
v. angulosum
29 x 17 μm
Near Omine-numa
Minakami
Gunma, 2008
C. angulosum
v. concinnum
14 x 12.5 μm
Tane-ike
Togakushi highland
Nagano, 2005