On Salix fragilis - Crack Willow
No identification made yet.
No interactions present.
The brown marks shown here don't key out as galls. They might be the result of insect feeding - there is a weevil species that produces such marks, but there would be an obvious thinning of the leaf where it has been eaten. Otherwise, the marks could be the result of a fungal infection.
Put it up as fungus, lets see what the fungi folk have to say.
An iSpot Project- HELP WITH IDS - UK & Ireland Community - PLANTS
Lat/Lng: 53.2055, -0.5631
OS grid ref: SK960685
Backies woods, Boultham Moor, Lincoln.