The oak woodland in the dry season. The Valley Oaks (Quercus lobata) form the background, still fully leafed out. The California Buckeye (Aesculus californica), the semispherical tree just to the left of center, is fast losing its leaves. It is adapted to the California rainless summer, and will sprout new leaves after the rainy season begins. Poison Oak (Toxicodendron diversilobum) shows many forms -- vines and shrubs -- and many have lovely bright red leaves.