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. ?,
cell body nearly spherical, 8-10 μm in diam.,
x 640, drainage ditch near Tama river, Fuchu city, Tokyo, March 10, 2004 by Y. Tsukii
94 μm; x 640