Genus: Unicellular; variable in shape; a constriction at the center of the cell body; mostly longer than wide; flattened; each semicell hemispherical, spherical, ellipsoidal, rectangular, pyramidal or kidney-shaped; no apical indentation.
Subgenus [ Eucosmarium ]: Cell body dorso-ventrally compressed, with strong constriction at the center, transverse section elliptical or diamond-shaped.
Section [ Ornatae ]: Semicells circular, ellipsoid, reniform; cell surface granulated or spiny (Illustrations of The Japanese Fresh-water Algae, 1977).
Species [ var. reniforme ]: Cell body medium in size, slightly longer than width, (47-56)-57 μm long, (32-34.4)-38-40 μm wide, isthmus 15-(17)-20 μm wide; semicells reniform, side view circular, apical view elliptical; cell wall covered with granules (Illustrations of The Japanese Fresh-water Algae, 1977).
Google Image Search
| Var. reniforme: Semicell reniform, apex convex | |||
C. reniforme var. reniforme 43 x 38 μm Koshigaya Saitama, 2001 |
C. reniforme var. reniforme 43 x 37 μm Kurihashi Saitama, 2001 |
C. reniforme ? var. reniforme 46 x 43 μm Muneoka Shiki Saitama, 2004 |
C. reniforme ? var. reniforme 44 x 40 μm Kodama Saitama, 2003 |
C. reniforme ? var. reniforme 48 x 40 μm near Takao-sakura p. Kitamoto Saitama, 2005 |
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| Var. compressum: Semicell compressed reniform, apex flat | |||
C. reniforme var. compressum 72 x 60 μm Kowashimizu Suwa Nagano, 2005 |
C. reniforme var. compressum ? 53 x 48 μm Umi-no-nakamichi Fukuoka, 2001 |
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| Var. elevatum: Semicell elongated reniform, posterior sides straight, parallel to each other | |||
C. reniforme var. elevatum 52, 56 x 36 μm Koigakubo marsh Tessei-cho Okayama, 2004 |
C. reniforme var. elevatum μm Kareki-numa Nikko Tochigi, 2008 |
C. reniforme var. elevatum μm Omine-numa 3 Minakami Gunma, 2008  |
C. reniforme var. elevatum μm Azami-ike 5 Norikura highland Nagano, 2007 |
