There are a few of these small plants growing in the mostly dry Lower Peters Canyon Reservoir.
I picked a leaf, shown in pictures 3-5, and it seemed to have mold at its base, which I showed in pictures 6-7.
The initial ID is based solely on iNaturalist's AI suggestion.
I found the Valley Oak I was looking for! This sapling is growing next to the Mountains to the Sea Trail, and appears to be unplanted. The tree has a plastic marker on it, shown in pictures 5-6. Unfortunately for me it currently has no galls.
Host to:
This tree has been posted by other users here:
There are a few of these small plants growing in the mostly dry Lower Peters Canyon Reservoir. It's growing on a dirt slope.