When it comes to mosses and lichens, even the RHS has little to say, perhaps because relatively little is known about them, and they almost always occur where they will, rather than being planted or sown. They do have their place in the garden though, unsung but enhancing bigger plants and providing plant nutrients, offering a habitat for insects and materials for birds’ nests, as well as catching the eye from time to time when there is not very much of interest at this time of year.
Mosses are grouped with liverworts, and there is a British Bryological Society which is devoted to them, http://www.britishbryologicalsociety.org.uk/. I doubt whether there is much known about moss that isn’t to be found somewhere in this site. Lichens have their devotees as well, at http://www.britishlichens.co.uk. But trying to identify an individual piece by reference to the information in these sites would be a big task.
It seems as though humidity is the factor on which mosses and lichens depend, so in general, the further west one goes, the more mosses and lichens there tend to be growing. I last visited the west coast of Argyll in the winter, and all the old trees were festooned with mosses and lichens – it seemed like a shaded square in Savannah! Here on the east side, they are fewer, and perhaps
appreciated more in consequence.
The one place where moss grows only too well here, is in our lawns. Aiming for the perfect lawn is not high in my list of priorities, and we are so shaded that moss is gradually replacing the lawns’ grasses. I am in favour of allowing this to continue, as our lawns remain
defiantly green in the face of drought, and require little mowing.
I am sure that the other mosses we have here are not in the least unusual. One, growing between the stone slabs on our terrace, is not found elsewhere, and this is probably because there is lime associated with the gaps between the slabs. We have a particular lichen growing on stone steps whose colour, almost that of the verdigris on weathered copper, we copied and used for the exterior woodwork of the house.