Two of the boundaries of the land at my sister's house consist of old (at least 1920s) stone walls known as dry state dikes (dry stone walls) built by careful selection of stones and their placement - no mortar is used to bind them.
The interfaces between the stones make natural places for mosses, lichens and some wild flowers. I spotted these when visiting today. I have no idea what they are but was struck by the contrast between the grey/white and the surrounding green.
I deliberately left the out of focus heads at the bottom uncropped.