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Gamophyceae: Zygnematales: Desmidiaceae or Closteriaceae

Closterium acutum
Brébisson var. acutum

Closterium 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).


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
scale 50 μm scale 100 μm scale 150 μm; x 400 : scale 31 μm scale 63 μm scale 94 μm; x 640
Closterium Closterium

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).


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