The genus Arceuthobium, commonly called dwarf mistletoes, is a genus of 26 species of parasitic plants that parasitize members of Pinaceae and Cupressaceae in North America, Central America, Asia, Europe, and Africa. Of the 42 species that have been recognized, 39 and 21 of these are endemic to North America and the United States, respectively. They all have very reduced shoots and leaves with the bulk of the plant living under the host's bark. Recently the number of species within the genus has been reduced to 26 as a result of more detailed genetic analysis.
Arceuthobium douglasii is a species of dwarf mistletoe known as Douglas fir dwarf mistletoe. It is native to western North America from British Columbia to Texas to California, where it lives in forest and woodland as a parasite. It is found mostly on Douglas fir trees, but occasionally on fir, as well.
Arceuthobium littorum is a species of dwarf mistletoe known as coastal dwarf mistletoe. It is endemic to the coastline of northern California, where it lives as a parasite on Bishop Pine and Monterey Pine trees. This is a dark brown or greenish shrub which is visible as a network of scaly stems extending above the bark of its host tree. Most of the mistletoe is located inside the host tree, attached to it via haustoria, which tap the tree for water and nutrients. The leaves of the mistletoe are reduced to scales on its surface.
Arceuthobium siskiyouense is a species of dwarf mistletoe known as knobcone pine dwarf mistletoe. It is endemic to the Klamath Mountains of northern California and southern Oregon, where it lives as a parasite on knobcone pine trees. This is a brownish shrub which is visible as a network of scaly stems extending above the bark of its host tree. Most of the mistletoe is located inside the host tree, attached to it via haustoria, which tap the tree for water and nutrients. The leaves of the mistletoe are reduced to scales on its surface.
Arceuthobium monticola is a species of dwarf mistletoe known as western white pine dwarf mistletoe. It is endemic to the Klamath Mountains of northern California and southern Oregon, where it lives as a parasite on western white pine trees.
Phoradendron californicum, the desert mistletoe or mesquite mistletoe, is a hemiparasitic plant native to southern California, Nevada, Arizona, Sonora, Sinaloa and Baja California. It can be found in the Mojave and Sonoran Deserts at elevations of up to 1400 m.
Phoradendron densum Trel. is a species of flowering plant in the sandalwood family known by the common name dense mistletoe. It is native to the western United States and northwestern Mexico, where it grows in various types of woodland habitat. It has been reported from California, Oregon, Arizona and Baja California. This mistletoe parasitizes species of cypress, including Arizona cypress, and juniper.
Phoradendron juniperinum is a species of flowering plant in the sandalwood family known by the common name juniper mistletoe. It is native to the southwestern United States and northern Mexico, where it grows in various types of woodland habitat. It has been reported from California, Nevada, Arizona, New Mexico, Oregon, Utah, Texas, Chihuahua and Sonora.
Phoradendron macrophyllum is a species of flowering plant in the sandalwood family known by the common names Colorado Desert mistletoe, bigleaf mistletoe, and Christmas mistletoe. It is native to western United States and northern Mexico from Oregon to Colorado to Texas to Baja California, where it grows in many types of wooded habitat at elevations up to 1700 m.
Phoradendron pauciflorum is a species of flowering plant in the sandalwood family known by the common name fir mistletoe. It is native to coniferous forests in California, Arizona, and Baja California.
Phoradendron tomentosum, the leafy mistletoe, hairy mistletoe or Christmas mistletoe, is a plant parasite. It is characterized by its larger leaves and smaller berries than dwarf mistletoe. Leafy mistletoe seldom kill but they do rob their hosts of moisture and some minerals, causing stress during drought and reducing crop productions on fruit and nut trees. Leafy mistletoe has the ability to photosynthesize on its own but it relies on other plants in order to obtain its nutrients. It attaches itself to a tree and then grows haustoria, in order to get the food and water it needs.
Arceuthobium apachecum, called the "Apache dwarf mistletoe," is a parasitic plant found on the branches of pine trees in Arizona, New Mexico and Coahuila. It has yellowish-green stems up to 7 cm high.
Arceuthobium microcarpum, called the "western spruce dwarf mistletoe," is a parasitic plant known only from Arizona and New Mexico. It is found mostly on spruce trees but also occasionally on Rocky Mountain bristlecone pine. The specific epithet "microcarpum" means "small fruited," in reference to the berries, which are only 3.5 mm long.
Arceuthobium vaginatum, called the "sheathed dwarf mistletoe" or "southwestern dwarf mistletoe" is a parasitic plant found in the southwestern United States and northwestern and central Mexico. It generally is found on pine trees.
Phoradendron capitellatum, the downy mistletoe or hairy mistletoe, is a hemiparasitic plant native to Arizona, New Mexico, Chihuahua and Sonora. It grows mostly on junipers at elevations of 800–1,700 m (2,600–5,600 ft). It is distinguished by having short, densely puberulent leaves usually less than 3 cm long. Flowers are also pubescent. Berries are pink to white, about 3 mm in diam.
Phoradendron coryae, Cory's mistletoe or oak mistletoe, is a hemiparasitic plant native to the southwestern United States and northern Mexico. It is reported from Arizona, New Mexico, Texas, Chihuahua, Coahuila and Sonora.
Arceuthobium pusillum is a perennial, obligate parasitic plant in the sandalwood family. Its common names include Dwarf mistletoe or Eastern dwarf mistletoe. It is one of the most widespread dwarf mistletoes within its range which covers the eastern United States and Canada, from Saskatchewan to Nova Scotia and New Jersey. The species name "pusillum" derives from Latin "pusillus", meaning very small.
Arceuthobium azoricum is a species of dwarf mistletoe endemic to the Azores. The population is restricted to the Grupo Central of the archipelago on Faial, Pico, São Jorge and Terceira islands. It is a parasitic plant of the local Juniperus brevifolia.
Lake Shore Gill was a botanist and forest pathologist for the U.S. Department of Agriculture. He was a definitive authority on the genus Arceuthobium.
