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 ??,
cell body nearly spherical, 6 μm in diam., with a pyrenoid,
x 640, Iruma river, Kami-terayama, Kawagoe city, Saitama Pref., Japan, January 18, 2004 by Y. Tsukii
94 μm; x 640