Genus: Filament without branching; cell body cylindrical; one or several chloroplasts band-shaped, spirally arranged within the cell, pyrenoids present; septum with or without folded structure (Guide book to the "Photomicrographs of the Freshwater Algae", 1998). About 300 species (Illustrations of The Japanese Fresh-water Algae, 1977). Species:

100 μm 200 μm 300 μm; x 200 : 50 μm 100 μm 150 μm; x 400

Spirogyra sp. (different species ?), cell body μm long, μm wide, a single band-form chloroplast making turns in each cell, x 100, x 200, x 400, x 640, Owada Park, Saitama city, Saitama Pref., Japan, April 3, 2005 by Y. Tsukii

x 400, x 640