California Lace Lichen -- aka Spanish Moss (Ramalina menziesii) on Valley Oak (Quercus lobata)
"Spanish Moss" is not a moss at all, but a Lichen -- here, a symbiosis between a fungus and an alga. The bright green of the new spring leaves on the Valley Oak contrasts with the blue-green of the lichen, and the darker green of the oak/fir woodland behind, across the San Andreas Fault. Flowers at the lower right.
