Growing on Quercus kelloggii
San Diego County, California, US
According to Calflora, it could either be P. serotinum macrophyllus or P. serotinum tomentosus.
In Quercus lobata
Earth Day Flower Survey with rangers and volunteers in the Rancho de Guadalupe Area.
In native oaks.
I found this mistletoe growing in an oak tree at the Pepperwood Preserve in Sonoma County.
Mistletoe (Phoradendron tomentosum)