Three Kinds of Oaks
On the left, a single valley oak (Quercus lobata). On the left of the hillside, a stand of blue oaks (Q. douglasii). To their right, rougher and less blue, the hillside is taken over by coast live oaks (Q. agrifolia). The difference is starker when the former two lose their leaves. The serpentine grassland has dried out; the other, lower grass remains green.