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Gamophyceae: Zygnematales: Desmidiaceae

Cosmarium pachydermum
var. ellipticum Hinode

Cosmarium pachydermum Species [var. pachydermum]: Cell body 78-117 μm long, 60-87 μm wide, isthmus 25-34 μm wide, semicells semielliptical in shape, corners rounded.
[var. aethiopicum W. et G.S. West ]: Semicells nearly half-circle; cellwall thin; cell body 64-107 μm long, 56-80 μm wide, isthmus 28-34 μm wide.
[var. ellipticum Hinode ]: Semicells rectangular at base; curvature of lateral margins weak compared to var. pachydermum; cell body 94-100 μm long, 67-74 μm wide, isthmus 28-34 μm wide.
[var. heptagonum Grönblad ]: Semicells irregular pentagon in shape; posterior half of lateral margins nearly straight; cell body 94-100 μm long, 67-74 μm wide, isthmus 28-34 μm wide (Illustrations of The Japanese Fresh-water Algae, 1977).
Similar species -->> C. lundellii; C. cucumis;


Cosmarium pachydermum var. ellipticum Hinode (or C. cucumis (Corda) Ralfs ?), cell body 114 μm long, 65 μm wide, isthmus 28 μm wide, x 400, x 640, Imou bog, Toyohashi city, Aichi Pref., Japan, September 11, 2004 by Y. Tsukii
scale 31 μm scale 63 μm scale 94 μm; x 640
Cosmarium Cosmarium Cosmarium

Cosmarium pachydermum P. Lundell var. pachydermum: Cell body 78-117 μm long, 60-87 μm wide, constriction (isthmus) 25-34 μm wide; semicells broad half-ellipsoidal, each corner rounded; side view nearly circular, apical view ellipsoidal; cell wall densely puncatated (Illustrations of the Japanese Fresh-water Algae, 1977)

Cosmarium lundellii P. Lundell var. circular: Cell body 53-73 μm long, 48-56 μm wide, constriction (isthmus) 17-25 μm wide; semicells broad semicircular, each corner rounded; apex narrowly straight; side view nearly circular, apical view elongated ellipsoidal; cell wall puncatated (Photomicrographs of the Fresh-water Algae, vol. 5, 1986).


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