Species [var. macilentum ]: Cell body large, elongated, both side nearly straight at central region, slightly tapered and curved toward ends, 260-(432-678)-800 μm long, 11-(14-21)-25 μm wide, L/W=25-40; cell wall smooth, transparent, bands present; 6-15 pyrenoids in each semicell.
[ var. japonicum ]: Cell body wider at the center and narrower at ends than var. macilentum, 400-(447-5780-600 μm long, 23-(32-34) μm wide, L/W=12-18; cell wall finely striated (Illustrations of The Japanese Fresh-water Algae, 1977).
T=terminal; Tv=terminal vacuole
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Similar species -- >> C. gracile;
var. japonicum: Cell body centrally wider than var. macilentum; 400-600 μm long, 23-34 μm wide, L/W= 12-18
C. macilentum
v. japonicum ?
728 x 28.5 μm
L/W=25.5
Onnenai
Kushiro marsh
Hokkaido, 2005
C. macilentum
v. japonicum
600 x 40 μm
L/W=15
Aizu Recreation p.
Aizuwakamatsu
Fukushima, 2005
C. macilentum
v. japonicum
524 x 47 μm
L/W=11.1
Igashira park
Mooka
Tochigi, 2006
C. macilentum
or praelongum ?
450 x 21 μm
L/W=21.4
near Tamogi-ike
Nabekura highland
Nagano, 2008
C. macilentum
v. japonicum
480 x 37 μm
L/W=13.0
Ko-numa 1
Minakami
Gunma, 2008
C. macilentum
v. japonicum
500 x 36 μm
L/W=13.9
Near Omine-numa
Minakami
Gunma, 2008var. macilentum: Cell body large; 260-800 μm long, 11-25 ╝m wide, L/W = 25-40
C. macilentum ?
v. macilentum
586 x 19 μm
L/W=30.8
Onnenai
Kushiro marsh
Hokkaido, 2005
C. macilentum
v. macilentum
290 x 10.5 μm
L/W=27.6
Suga-daira m.
Ueda
Nagano, 2006
C. macilentum
v. macilentum
210 x 10.5 μm
L/W=20
Naruto-Togane
Sanmu
Chiba, 2006
C. macilentum
v. macilentum
263 x 11 μm
L/W=23.9
Suiren-numa
Hakkoda mountain
Aomori, 2005
C. macilentum
v. macilentum ?
255 x 8 μm
L/W=31.9
Higashi-sano
Hakuba
Nagano, 2004
C. macilentum
or C. aciculare ?
262 x 5.5 μm
L/W=47.6
Ochiai-numa 2
Noshiro
Akita, 2007
C. macilentum ??
640 x 15 μm
L/W=42.7
Kareki-numa
Nikko
Tochigi, 2008