Window sill on my house.
Snow overnight, around zero all day.
The window-sill is concrete, and about 7 years old, and the lichens started to appear almost straight away. It's interesting to note that they start to make fruiting bodies almost immediately. Identifications are very difficult at this stage, but I've made one or two valiant efforts.
This is Physcia
tenella, with little pieces of Xanthoria parietina. Central
specimen about 12 mm across.
These specimens are about 8 mm across, and the fruitbodies are clearly visible. Again, Xanthoria parietina appears to be a dominant species, living directly on top of other specimens. I'm not sure if it's parasitic, or if it just doesn't care where it grows.
The specimen with the pale-green fruit bodies appears to be a Lecanora, perhaps Lecanora campestris. And the specimen with darker fruit-bodies appears to be Candelariella aurella.