Genus: Cell body small, length = width, strong constriction at its center; semicells inverted triangular, ellipsoidal, rectangular, etc. in shape; straight or slightly curved spiny projections at each corner; one pyrenoid in each semicell; cell wall smooth (Illustrations of The Japanese Fresh-water Algae, 1977).
Species:
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A. convergens
33 x 38 μm
31 x 33 μm
Maimeno-ike
Norikura highland
Nagano, 2006
A. convergens
μm
Maimeno-ike 2
Norikura highland
Nagano, 2007
A. convergens
μm
Kareki-numa m.
Nikko
Tochigi, 2008.8
A. convergens
μm
Kareki-numa m.
Nikko
Tochigi, 2008.9