One Valley Oak carrying many types of galls including this one
Small spherical galls about 4mm in diameter on underside of Live Oak leaf. Formed by some sort of Cynipid wasp.
Gouty oak gall, Callirhytis quercuspunctata, on on post oak, Quercus stellata.
Gall wasps (Cynipidae), also called Gallflies, are a family of the order Hymenoptera and are classified with the Apocrita suborder of wasps in the superfamily Cynipoidea. About 1300 species of this generally very small creature (1-8 millimeters) are known worldwide, with about 360 species of 36 different genera in Europe and some 800 species in North America.
