Oxbow Preserve on planted California Wild Rose
On Cottonwood.
Gall on poplar.
on Fremont cottonwood
On Populus fremontii
one gall is near the Downy Woodpecker's foot, another is to its left
On Populus fremontii
On Cottonwood
Host - Alnus acuminata
@nancyasquith do you know this?