Gamophyceae:
Zygnematales: Desmidiaceae or Closteriaceae
Closterium acutum
Brébisson var. acutum
Genus: Cell body crescent in shape (long, curved, tapered at both ends); cross section rounded;
cell wall smooth or with longitudinal lines, bands on the cell wall in some species;
chloroplast laminae ridged and radially arranged, which makes cross section star-shaped;
pyrenoids aligned or scattered (Illustrations of The Japanese Fresh-water Algae, 1977).
Species [var. acutum]:
Cell body slightly curved, tapered at rear, L/W= 20-30; both termini broad circle;
cell wall smooth, transparent; chloroplasts with 3-4 pyrenoids in each semi-cells;
90-(92-176) μm long,
4-(4.8-8.4) μm wide
(Illustrations of The Japanese Fresh-water Algae, 1977).
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Closterium acutum,
cell body 110-130 μm long, 4 μm wide, L/W=27.5-32.5,
x 640, Komado marsh (or bog), Showa village and Tajima town, Fukushima Pref., Japan, August 22, 2004, by Y. Tsukii
50 μm
100 μm
150 μm; x 400 :
31 μm
63 μm
94 μm; x 640
cf.
C. toxon W. West:
163-(190-350) μm long,
8-(8.4-13)-20 μm wide;
L/W = 25-33;
cell body slightly curved; both termini broadly rounded (nearly truncated);
cell wall transparent, smooth; 5-7 pyrenoids arranged in a single line
(Illustrations of The Japanese Fresh-water Algae, 1977).
C. cornu Ehrenberg var. cornu:
Cell body slightly curved, tapered at rear, L/W= 16-17; both termini broad circle;
cell wall smooth, transparent; chloroplasts with 3-4 pyrenoids in each semi-cells;
95-160 μm long,
5-(7.8-13) μm wide
(Illustrations of The Japanese Fresh-water Algae, 1977).
Please click on images for viewing enlarged.
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