Closterium

Gamophyceae: Zygnematales: Desmidiaceae
(Charophyceae: Zygnematales: Desmidiaceae)

 Closterium acerosum

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).
T=terminal; Tv=terminal vacuole

Closterium (acerosum ?), μm long, μm wide, x 100, x 200, x 400, x 640, Uruguay Nov. 1999, photo by Yuuji Tsukii
scale 50 μm scale 100 μm scale 150 μm; x 400 : scale 31 μm scale 63 μm scale 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 half-cell (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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