These are solitary or irregularly clustered single-celled green algae that lack motility. They typically display a spherical or ellipsoidal shape, with diameters ranging from 2 to 12 µm, although sizes may vary. Their chloroplasts are generally parietal, taking on a cup-shaped or plate-like structure, and occasionally contain pyrenoids. Reproduction is asexual and occurs through mitosis, with the cells acting as autospores.