Arceuthobium campylopodum

Arceuthobium campylopodum, commonly known as western dwarf mistletoe, is a species of flowering plant in the family Santalaceae. It is native to the low to moderate elevation coniferous forests of western North America. Like other dwarf mistletoes, A. campylopodum parasitizes several species of conifers pine tree, including the Jeffrey pine, ponderosa pine, and Coulter pine. The impact of A. campylopodum on the ecology and commercial productivity of conifer forests is significant. Infections by A. campylopodum decrease the vigor and longevity of host trees, induce deformed growths called witch's brooms, and increase host susceptibility to other pathogens. At the same time, A. campylopodum is an essential food source to wildlife, including some species of hairstreak butterflies whose larvae feed only on dwarf mistletoes. Since its formal description by George Engelmann in 1850, the treatment of A. campylopodum has been a source of taxonomic contention. Some taxonomic authorities, including The Jepson Manual, apply a broad circumscription of A. campylopoda, encompassing most or all of the 13 species in the taxonomic section Campylopoda. This article applies the narrower circumscription of A. campylopoda sensu stricto.

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