Species: Cell body elongated spindle-shaped, 220-(240-312) μm long, (10-11)-14 μm wide, L/W=20-26 (cf. C. strigosum,150-410 μ L/W=10-18); cell wall transparent, smooth; chloroplasts with 3-6 pyrenoids (Illustrations of The Japanese Fresh-water Algae, 1977).
Cell body (110-)150-250(-310) μm long, (6-)8-12(-14) μm wide; L/W=(12-)15-30(-35) (Coesel & Meesters 2007).
Google Image Search
L/W around 20-30
C. idiosporum
278 x 8 μm
L/W=34.8
Ohyachi 2
Kazuno
Akita, 2007
C. idiosporum ?
293 x 11.5 μm
L/W=25.5
Ohyachi 1
Kazuno
Akita, 2007
C. idiosporum
270,328 x 10 μm
L/W=26,33
Gozaisho marsh
Hachimantai
Iwate, 2005
C. idiosporum
247 x 7.5 μm
L/W=32.9
Sensho-ga-hara 4
Shizukuishi
Iwate, 2007
C. idiosporum
140 x 5 μm
L/W=28
Tojuro
Azuma mt.
Yamagata, 2007
C. idiosporum ?
202-240 x μm
L/W=27-31
Sukawa highland
Kurikoma mountain
Akita, 2005
C. idiosporum
224 x 7 μm
L/W=32
Tashirodaira m.6
Hakkoda mountain
Aomori, 2006
C. idiosporum
230 x 7 μm
L/W=33
Shibakusadaira
Zao mountain
Miyagi, 2007
C. idiosporum
185 μm
L/W=33.6
Kejo-numa
Furukawa
Miyagi, 2003
C. idiosporum
123 x 4 μm
L/W=30.8
Iroha-numa
Zao mountain
Yamagata, 2005
C. idiosporum
190, 230 x 7 μm
L/W=27, 33
Komado marsh
Showa and Tajima
Fukushima, 2004
C. idiosporum
202 x 9, 295 x 8
L/W=22, 32
Numa-no-hara marsh
Madarao highland
Niigata, 2005
C. idiosporum
200 x 5.5 μm
L/W=26-32
Tokyo, 2001
C. idiosporum
225 x 6.5 μm
L/W=34.6
Fujimitashiro
Katashina
Gunma, 2007
C. idiosporum
115-223 x 4-7 μm
L/W=29-32
Watasuge marsh
Tsugaike highland
Nagano, 2006
C. idiosporum
120-122 x 3-4 μm
L/W=27,31
Ukishima marsh
Tsugaike highland
Nagano, 2005
C. idiosporum
218 x 6.5 μm
L/W=33.5
near Okubo ike
Shinano
Nagano, 2004
C. idiosporum
173 x 4.5 μm
L/W=28.7
Ichinose-enchi
Norikura highland
Nagano, 2005
C. idiosporum
240 x 8 μm
L/W=30
Chigo-ike
Shiga highland
Nagano, 2006
C. idiosporum
205 x 7 μm
L/W=29.3
Kuroyachi m.2
Hachimantai
Iwate, 2007
C. idiosporum
278,213 x μm
or C. gracile ?
L/W=35,43
Kejo-numa
Osaki
Miyagi, 2006L/W nearly 20 (intermediate ?)
C. idiosporum
or C. strigosum ?
195 x 8.5 μm
L/W=22.9
Imori pond
Myoko highland
Niigata, 2004
C. idiosporum
or C. strigosum ?
142 x 6.5 μm
L/W=21.8
rice field
Omiya-showa
Saitama, 2005
C. idiosporum
or C. strigosum ?
115, 117 x 4.5 μm
L/W=25.6-26
Tanohara marsh
Shiga highland
Nagano, 2004
C. idiosporum
or C. strigosum ?
131 x 3 μm
165 x 6 μm
L/W=21.8, 27.5
near Yamaguchi Univ.
Yamaguchi, 2004
C. idiosporum
210 x 12.5 μm
L/W=
Azami-ike
Norikura highland
Nagano, 2006
Similar species -->> C. pronum ( μ, L/W=30-45); C. acutum ( μ, L/W= 20-30); C. strigosum (150-410 μ, L/W=10-18); C. aciculare (390-800 μ, L/W=73-135); C. gracile (90-275 μ, L/W=25-40);