Species: Cell body quickly attenuated toward both ends (cf. C. ralfsii), 
each extended part shorter than spindle-shaped part at middle (cf. C. setaceum), 
both termini slighlty curved, rounded, 270-690 μm long, 14-27 μm wide ( L/W= 18-20); 
cell wall transparent or brownish with thin lines (8-10 lines/10 μm wide); 
chloroplasts composed of 5 lamellae; 4-6 pyrenoids in each half-cell 
(Illustrations of The Japanese Fresh-water Algae, 1977). 270-512 μm long, 13-22 μm wide ( L/W= 18-30); 8-11 lines/10 μm wide (Photomicrographs of the Fresh-water Algae, vol. 4, 1985).  | 
Closterium kuetzingii, 
cell body 310 μm long, 20.5 μm wide, L/W=15.1, 
x 200, x 400, x 640, No.1, Iyari marsh, Omachi city, Nagano Pref., Japan, June 4, 2007 by Y. Tsukii
 50 μm
 100 μm
 150 μm; x 400 : 
 31 μm
 63 μm
 94 μm; x 640
Cell body 366 μm long, 21 μm wide, L/W=17.4, x 640
Cell body 444 μm long, 20 μm wide, L/W=22.2, x 640
Images of collecting locality: 
No.1, Iyari marsh, Omachi city, Nagano Pref., Japan, June 4, 2007 by Y. Tsukii