Scenedesmus Meyen
From Greek skene, "tent or awning" + desmos, "bond"
More than 100 described species are distinguished by the number and arrangement of cells and the ornamentation pattern on the cell wall.
Scenedesmus is a small, nonmotile colonial green alga consisting of cells aligned in a flat plate. The colonies most often have two or four cells, but may have 8, 16, or rarely 32 and are occasionally unicellular. The cells are usually cylindrical but may be more lunate, ovoid, or fusiform. Typically the end cells each have two long spines up to 200 µm in length protruding from their outer corners, and other cells may have additional spines or chitonous bristles. Each cell contains a single parietal, plate-like chloroplast with a single pyrenoid. The cell walls may be covered in bumps or reticulations that are best viewed with scanning electron microscopy.