Oocystis

Oocystis is a planktonic genus of mostly freshwater green algae of the family Oocystaceae. It is the type genus of its family. Oocystis is mostly found in freshwater habitats and has a cosmopolitan distribution. A few species are found in terrestrial, such as wet rocks, or in marine waters.

==Description== Oocystis is solitary or borne in colonies of two, four or eight surrounded in a thin mucilaginous envelope or mother cell wall. The colony is up to 77 μm in diameter and oval to ellipsoid. Individual cells may be fusiform, ellipsoidal, oval or nearly spherical, 7–46 μm long. The cell wall is smooth but may be thickened at the poles. Cells contain one to many parietal chloroplasts.