Arceuthobium siskiyouense

Arceuthobium siskiyouense is a species of dwarf mistletoe commonly known as knobcone pine dwarf mistletoe and as Arceuthobium campylopodum subsp. siskiyouense. It is endemic to the Klamath Mountains of northern California and southern Oregon, where it parasitizes a number of species of hard pines in the subgenus Pinus. Its ecological impact on the coniferous forests where it is found is significant, both because of its negative impact on the health of infected trees and because it provides food and microhabitats (by inducing witch's brooms) for other wildlife....read more on Wikipedia.