The asterisk marks by some of the lichens below indicates that I recognise at least some members of the genus. Any input from the group on these or other lichens would be greatly appreaciated.
Lichens are a symbiotic association between algae and fungus.
The algae is a layer of single-celled plants on the surface, just below a gelatinized layer of fungal hyphae. These are otherwise independent organisms, capable of surviving without each other. Lichens can insert threads a half inch into solid rock. These threads are not true roots, but anchors. The fungus produces a potent acid, which is combined with an alcohol from the algae to form acid crystals.