 
 
Gamophyceae: 
Zygnematales: Desmidiaceae or Closteriaceae
Closterium acerosum
(Schrank) Ehrenberg ex Ralfs 1848
|  Species: 
250-(396-576)-790 μm long, 25-(33-84) μm wide; 
cell body large, slightly curved; both termini tapered; pyrenoids 7-15 in each semicell 
(Illustrations of The Japanese Fresh-water Algae, 1977).  
Cell body slightly curved, gradually attenuated toward the truncated ends, which somewhat recurved 
due to the covexity of the inner margin near the ends; inner margin straight or slightly concave, 
outer margin convex, 300-500 μm long, 32-50 μm wide, L/W=9-14; 
cell wall smooth and colorless or sometimes delicately striated and yellowish-brown in color; 
chloroplasts with ridges containing 7-11 pyrenoids in central row 
(Photomicrographs of the Freshwater Algae, vol. 1, 1984). | 
Closterium sp., a dividing cell ?, 
cell body 575 μm long, 43 μm wide, L/W = 13.4, 23 pyrenoids (?), 
x 200, x 400, Japan, 1998 by Y. Tsukii
 50 μm
 50 μm
 100 μm
 100 μm
 150 μm; x 400 :
 150 μm; x 400 : 
 31 μm
 31 μm
 63 μm
 63 μm
 94 μm; x 640
 94 μm; x 640
 
 
 
 
 
 
 
 
C. acerosum (Schrank) Ehrenberg var. acerosum: 
250-(396-576)-790 μm long, 
25-(33-84) μm wide; 
cell body large, slightly curved; both termini tapered; 
pyrenoids 7-15 in each semicell 
(Illustrations of The Japanese Fresh-water Algae, 1977). 
C. acerosum var. elongatum Brébisson: 
650-(773-780)-915 μm long, 
(30-38)-40 μm wide; 
L/W = 15-33 
(Illustrations of The Japanese Fresh-water Algae, 1977). 
C. acerosum var. minus Hantzsch: 
200-300 μm long, 
18-25 μm wide; 
L/W = 7-11 
(Illustrations of The Japanese Fresh-water Algae, 1977). 
C. acerosum var. tumidum Borge: 
Slightly swell at center; 
336-(384-494) μm long, 
35-(42) μm wide; 
L/W = 8-12 
(Illustrations of The Japanese Fresh-water Algae, 1977). 
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