Pleurotaenium

Pleurotaenium is a genus of green algae, specifically of the desmids (Desmidiaceae). It is a cosmopolitan genus, with about 50 species. Members of Pleurotaenium are found in freshwater habitats, and may be found in acidic, neutral or alkaline waters.

==Description== Pleurotaenium consists of long, cylindrical, bilaterally symmetrical cells with blunt ends; they are typically solitary, but occasionally joined end-to-end to form filaments. There is a shallow median constriction (an isthmus), where the two halves (called semicells) of the cells are joined. Semicells are widened at the base and truncate at the apex. At each apex, there is a vacuole filled with small granules. The cell wall is covered in fine pores, and may have mammillate protuberances, or spines. Cells have multiple chloroplasts, which are parietal bands from base to apex; these typically have several pyrenoids. The nucleus is at the isthmus.