LM of a section through the lobe of Peltigera aphtosa,through a Cephalodium. The thallus is dotted with cephalodia,which contain one of the two symbionts,a cyanobakterium,species Nostoc,identifiable by the olive-green color. Nostoc is located inside the Cephalodia in small clusters. The other symbiont,a green alga genus Coccomyxa,is located under the surface of the lobe in a thin,continuous layer,seen at the bottom of the image. Microscopic contrast method : Differential interference contrast. Magnification 380x when printed at 10 centimetres wide |