Quercus dumosa
"Root" galls
Globular, smooth, dia 5 mm, detachable. Found only once. Empty in August.
- LH Weld: (1957) Cynipid Galls of the Pacific Slope©
Reference: https://babel.hathitrust.org/cgi/pt?id=coo.31924018313555&view=1up&seq=63&skin=2021