Genus: Unicellular or colonial within a gelatinous sheath; planktonic; cell body spherical;
1 or several chloroplasts cup-shaped, with a pyrenoid
(Guide book to the "Photomicrographs of the Freshwater Algae", 1998).
Similar genus --> Dictyosphaerium Planktosphaeria sp. (Chlorococcales, Chlorophyceae),
cell body μm long, μm wide, a pyrenoid present,
x 640, near Yanase river, Mizuko, Fujimi city, Saitama Pref., Japan, December 2003 by Y. Tsukii
94 μm; x 640