Oocystaceae

Oocystaceae is a family of green algae, in the class Trebouxiophyceae. Molecular phylogenetic studies mostly (but not always) place the family in the order Chlorellales, as sister to Chlorellaceae. The type genus is 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.

Lagerheimia is a genus of green algae in the family Oocystaceae. It is commonly found in freshwater habitats all over the world, although some species are rare and have only been recorded from Europe or the United States.