Closterium setaceum ??, x 400, x 640, Aug. 7-13 1999, Vermont-Maine U.S.A., by Y. Tsukii
* Closterium setaceum Ehrenberg var. setaceum f. setaceum: Cell body small in size, elongate, L/W= 30-42, 252-528 μm long, 6-16 μm wide; both termini slightly curved, spindle-shaped at middle; cell wall transparent or brownish with thin lines (8-13 lines/10 μm wide); 2-3 pyrenoids in each half-cell (Photomicrographs of the Fresh-water Algae, vol. 6, 1997).
Closterium kuetzingii Brébisson var. kuetzingii: Cell body moderate in size, elongate, L/W= 18-30, 270-512 μm long, 13-22 μm wide; both termini slightly curved, spindle-shaped at middle; cell wall transparent or brownish with thin lines (8-11 lines/10 μm wide); chloroplasts composed of 5 lamellae; 4-6 pyrenoids in each half-cell (Photomicrographs of the Fresh-water Algae, vol. 4, 1985).