Closterium dianae is a freshwater green algae belonging to the desmid group. It has elongated, crescent-shaped cells with a thin cellulose cell wall. Each cell contains ribbon-like chloroplasts with pyrenoids for starch storage. Reproduction occurs primarily through binary fission, and sexual reproduction via conjugation is also possible. Closterium dianae is commonly found attached to submerged vegetation or sediment in ponds, lakes, and slow-moving streams, where it plays a vital role as a primary producer in aquatic ecosystems.