maple leaf

[thedeeredude]

Here's a maple leaf that's got something funky going on.  The tree is in an open park and not in the best of health.  What is it and what's causing it?

[Jeff]

Its a leaf gall. Probably has nothing to do with the health of the tree and most likely won't harm it. Its plant tissue that developed probably do to the feeding of some sort of insect. I think the one pictured is called a Spindle Gall caused by leaf mites.

[Jeff]

I stepped out back and grabbed a picture of some galls on a pin cherry

in my back yard