Stereocaulon tomentosum
wooly foam, eyed foam lichen, tomentose snow lichen
It snowed a lot here in southern Germany over the weekend, and looking out over a sea of undifferentiated white blobs reminds me of my time spend trying to identify Stereocaulon lichens. S. tomentosum can be differentiated from similar looking white blobby lichens by the gray tomentum covering the pseudopodetial stalks, and dark-brown to black, convex apothecia on the lateral branches. It can be found in boreal-montane regions of the northern hemisphere, growing on mineral soil and among mosses. It, like other Stereocaulon lichens, is tripartite, meaning it has both green algal AND cyanobacterial photobionts. S. tomentosum keeps its cyanobacterial photobiont in special structures called cephalodia, which are burried in the tomentum on the underside of the granular phyllocladia (the granular branches).
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