Gray pine dwarf mistletoe.

Gray pine dwarf mistletoe (Arceuthobium occidentale) is an important parasite of gray, or foothill, pine (Pinus sabiniana) in California. This dwarf mistletoe does not occur outside of California and is common throughout the range of gray pine in the foothills of the Sierra Nevada Mountains and Coast Ranges around the Central Valley. It occurs in the Coast Ranges from Ventura County north to Siskiyou County (Figure 1). Although this dwarf mistletoe occurs primarily on gray pine (formerly Digger pine), it also commonly infects Coulter pine (Pinus coulteri) and knobcone pine (Pinus attenuata) where these species are associated with infected gray pines. Two other pines that may be infected in the Coast Ranges are ponderosa pine (Pinus ponderosa) and Jeffrey pine (Pinus jeffreyi). In addition, Monterey pine (Pinus radiata) and some other pines not native