Feron californicum (Hymenoptera: Cynipidae)
near Cactus Spring Trailhead, Pinyon Pines, San Bernardino National Forest, Riverside County, California
May 18, 2022

Wasp gall on Quercus cornelius-mulleri. Beutenmuller's 1911 species description fits Trichoteras californicum well in terms of the gall. There is also a chance this could be a different (but undescribed) species.