The comparative distribution and abundance of Phoradendron villosum subsp. villosum were described on three species of California oaks (Quercus agrifolia, Q. douglasii, and Q. lobata ) at 21 field sites between San Francisco and Santa Barbara. The occurrence of the mistletoe varied with geography, host species, and host size. Quercus agrifolia , an evergreen black oak, was virtually uninfested at the sites north of Arroyo Grande but was infested south of Arroyo Grande. In contrast, Q. douglasii and Q. lobata , both deciduous white oaks, were infested at northern and southern sites. Infested trees tended to be larger than uninfested trees in the three host species. There were no differences among the host species in the number of mistletoes occurring on infested trees.