Oaks are great for people seeking intellectual stimulations. With infinite variety, oaks never get boring, and challenge even the sharpest human observer to discern their subtle patterns. Above are shown leaf galls on an oak at the Shields Grove, similar to galls that can be found on native deciduous oaks through much of California. In the Shields Grove, the large tree these galls grow on is marked California Blue Oak (Quercus douglasii). But careful study of the leaves, branching structure, acorn peduncle, and bark show characteristics outside the range of Blue Oak to be found in California. Some suspected the tree is a hybrid, likely from Dr. Cottam at the University of Utah, as that's the origin of many trees growing near to this one in the Shields Grove.