The Daily Post Photo Challenge is Enveloped. I missed the initial announcement of it as I was so wrapped up in a book. I was reading The Lost Garden by Katharine Swartz on its UK publication date. The link is to Amazon, but please support local bookshops.
The photo I have chosen is from the place on which her imaginary Goswell is based. Her characters would have known this south-facing wall adjacent to a public footpath.
Surprisingly, the wall is a miniature nature reserve. It is covered in lichens and mosses. Ferns, ivy-leaved toadflax and other plants sprout from its crevices. In winter colonies of garden snails hibernate in cracks. The photo was taken on 9th May 2015 by which time many snails had ventured forth in search of vegetation to consume. (There are two near the middle of the picture.)