Light micrograph of the freshwater green alga Scenedesmus spec. Scenedesmus forms colonies of usually four or eight, unflagellated, elliptical cells arranged in rows, with a nucleus and a chloroplast with pyrenoid. The cells at the ends of the colonies often have spines as protection against feeding. Culture material of the algae collection at the University of Cologne (CCAC). Microscopic contrast method : Differential interference contrast. Magnification 920x at a print width of 10 cm.