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Ulvophyceae: Ulotrichales: Ulotrichaceae

Geminella ellipsoidea
(Prescott) Smith

Geminella Genus: Filamentous algae without branching, no rhizoids, covered with gelatinous sheath; cell body cylindrical or ellipsoidal, cells attached side by side or separated; a single chloroplast band-form, with a pyrenoid (Guide book to the "Photomicrographs of the Freshwater Algae", 1998).
Species: Filament covered with a thick gelatinous coat; 2 or 4 cells closely contacted; cell body elongated ellipsoid or ovoid, 4-6 μm long, 7-9 μm wide; chloroplasts parietal, with a single pyrenoid (Photomicrographs of the Freshwater Algae, vol.4, 1985).


Geminella ellipsoidea (or Microspora sp. ?), cell body 9 μm long, 6 μm wide, x 640, Nasuno-ga-hara museum, Nishi-nasuno town, Tochigi Pref., Japan, May 3, 2004 by Y. Tsukii
scale 50 μm scale 100 μm scale 150 μm; x 400 : scale 31 μm scale 63 μm scale 94 μm; x 640
Geminella Geminella Geminella
Cell body spherical, 7 μm in diam., flagella about 10 μm long, x 640
Geminella Geminella Geminella

Geminella mutabilis (Brébisson) Wille: Colonies linear filaments consisting of 10-20 cells; cell body short cylindroid, both ends rounded, 15-20 μm long, 8-10 μm in diam.; cells separated each other; a single chloroplast plate-like, with a pyrenoid (Illustrations of the Japanease Freshwater Algae, 1977). The thickness of the gelatinous sheath variable; planktonic; cell body ellipsoidal or cylindrical with rounded ends, 25-35 μm long, 9-20 μm in diam.; cells scarcely adherent to each other or equally separated one another; chloroplasts a single, plate-like forming a girdle, with a pyrenoid (Photomicrographs of the Fresh-water Algae, vol. 3 (1985).

Geminella ellipsoidea (Prescott) Smith var. ellipsoidea: Linear short filaments, free-floating, covered with a thick gelatinous sheath; cell body elliptic to ovate, 4-6 μm long, 7-9 μm in diam., transversely arranging in groups of 2 or 4 cells; a single chloroplast parietal, band-form, with a pyrenoid (Photomicrographs of the Fresh-water Algae, vol. 4 (1985).

Geminella planctonica Iyengar & Philipose: Thalli unbranched, short filaments clearly constricted at the cross wall, without mucilaginous sheath; cell body elontate cylindrical, 3-5 μm broad at the cross wall, 4-7 μm broad at the mid region of the cell; 8-24 μm long; chloroplasts a single, parietal, usually occupying the entire length of the cell; with 1-2 pyrenoids; (Photomicrog. Freshw. Alg. 13: 21, 1994)

Geminella minor (Nägeli) Hansgirg: Colonies a short lnear filament covered with a gelatinous sheath; cell body short cylindroid, 8-18 μm long, 4-8 μm wide; adjacent cells attached with each other (Illustrations of the Japanese Freshwater Algae, 1977).


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