Looks like a cherry tree growing in back yard woods, mostly in the shade. Bottom branches have these growths on the leaves in random spots. Stem of protuberance attaches to a conical deformation of the leaf, with plant veins growing up into the stem. This year is the first time I have seen these on the tree.
Is it a flower?
It is a leaf gall. Weird but not fatal.
https://en.wikipedia.org/wiki/Eriophyes_cerasicrumena#:~:text=Eriophyes%20cerasicrumena%2C%20the%20black%20cherry,also%20on%20the%20mites%20themselves.
Thanks for the quick response. I hadn't heard 'gall' except with 'stones'. I added it to my previous 'leaf' searches and found all the information about it. Weird, indeded.
Some of these are due to bugs depositing an egg in the leaf. Some of these are due to a fungus. My guess would be the latter in this case.
