Light micrograph of the freshwater green alga Oedogonium spec. Oedogonium has unbranched cell filaments with the nucleus in the middle, the chloroplasts are reticulate with pyrenoids. On the right of the picture, a rhizoid can be seen with which the germinating spore of Oedogonium attaches itself to the substrate. Culture material of the algae collection at the University of Cologne (CCAC). Microscopic contrast method : Differential interference contrast. Magnification 600x at a print width of 10 cm.