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Gamophyceae: Zygnematales: Desmidiaceae

 Staurastrum biexcavatum
Hirano var. biexcavatum

Staurastrum biexcavatum Genus: Cell body short, radiate in shape; apical view of the cell, triangular, polygonal, ellipsoidal or spindle-shaped; zygospores formed outside of mother cells (Illustrations of The Japanese Fresh-water Algae, 1977)
Subgenus: with arm-like projections (Illustrations of The Japanese Fresh-water Algae, 1977)
Species:

Staurastrum biexcavatum Hirano var. biexcavatum, cell body 33 μm long (including arms), 11 μm long (excluding arms), 36 μm wide, L/W=0.9, isthmus 5 μm wide, x 640, a small pond at Obihiro University of Agriculture and Veterinary Medicine, Obihiro city, Hokkaido, Japan, October 13, 2005 by Y. Tsukii
scale 31 μm scale 63 μm scale 94 μm; x 640
Staurastrum biexcavatum Staurastrum biexcavatum Staurastrum biexcavatum

Staurastrum biexcavatum Hirano var biexcavatum: Body with arms 40-41 μm long (including arms), 35-38 μm wide (including arms), constriction 8 μm wide; small; body length slightly longer than width; constriction moderate; hemicells V-shaped, with flattened apex and arm-like projections at both edges; the projections tapered, consisting of about 7 segments, 3 spines at terminal (Illustrations of The Japanese Fresh-water Algae, 1977)

Staurastrum biexcavatum var binodulum Hirano: Body with arms 34.4 μm long, 41 μm wide, constriction 65 μm wide; apex of hemicells slightly convex; swells at base of the arm-like projections (Illustrations of The Japanese Fresh-water Algae, 1977)

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