The long sinuous gallery that crosses the midrib suggests the micro moth Lyonetia clerkella, the Apple Leaf Miner. It affects many Prunus tree species.
Cherry Leaf Miner taking a line for a walk (a la Paul Klee, see below)
I particularly like the areas still chlorophyll-green, protected from the general yellowing by the tunnels of the leaf miner.
Burdened Children 1930 Paul Klee taking a line for a walk, having observed Cherry Leaf Miners at work (I made up this last bit)
The English seem unemotional … except for their passion for nature
