Sphaerocystis is a genus of green algae, specifically of the class Chlorophyceae.

[1] Sphaerocystis consists of cells embedded in spherical, gelatinous colonies up to 1 mm in diameter.

Autospores are formed in twos, fours, or eights and are released by the dissolution of the parent cell wall.

Zoospores have two apical flagella and have a single cup-shaped chloroplast with a pyrenoid.

[1] Sphaerocystis is similar in morphology to other genera, namely Coenochloris, Coenococcus, and Coenocystis.