The

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

''Arceuthobium'', commonly called dwarf

mistletoe Mistletoe is the common name for obligate hemiparasitic plants in the order Santalales. They are attached to their host tree or shrub by a structure called the haustorium, through which they extract water and nutrients from the host plant ...

s, is a genus of 26 species of

parasitic plant A parasitic plant is a plant that derives some or all of its nutritional requirements from another living plant. They make up about 1% of angiosperms and are found in almost every biome. All parasitic plants develop a specialized organ called the ...

s that parasitize members of

Pinaceae The Pinaceae, or pine family, are conifer trees or shrubs, including many of the well-known conifers of commercial importance such as cedars, firs, hemlocks, larches, pines and spruces. The family is included in the order Pinales, formerly know ...

and

Cupressaceae Cupressaceae is a conifer family, the cypress family, with worldwide distribution. The family includes 27–30 genera (17 monotypic), which include the junipers and redwoods, with about 130–140 species in total. They are monoecious, subdio ...

in North America,

Central America Central America ( es, América Central or ) is a subregion of the Americas. Its boundaries are defined as bordering the United States to the north, Colombia to the south, the Caribbean Sea to the east, and the Pacific Ocean to the west. ...

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an ...

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located enti ...

, and

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

. 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 (mostly reduced to scales) 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.

Description

They are

dioecious Dioecy (; ; adj. dioecious , ) is a characteristic of a species, meaning that it has distinct individual organisms (unisexual) that produce male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproducti ...

, individual plants being either male or female. The

fruit In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering. Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in partic ...

is unusual in that it builds up hydrostatic pressure internally when ripe and shoots the single sticky

seed A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiosper ...

up to speeds nearly , an example of

rapid plant movement Rapid plant movement encompasses movement in plant structures occurring over a very short period, usually under one second. For example, the Venus flytrap closes its trap in about 100 milliseconds. The traps of Utricularia are much faster, closin ...

. The lodgepole pine dwarf mistletoe,'' Arceuthobium americanum, has been found to explosively-disperse its seeds through

thermogenesis Thermogenesis is the process of heat production in organisms. It occurs in all warm-blooded animals, and also in a few species of thermogenic plants such as the Eastern skunk cabbage, the Voodoo lily ('' Sauromatum venosum''), and the giant w ...

.
Rolena A.J. deBruyn, Mark Paetkau, Kelly A. Ross, David V. Godfrey & Cynthia Ross Friedman. Thermogenesis-triggered seed dispersal in dwarf mistletoe. Dwarf mistletoe seeds are enveloped in a

hygroscopic Hygroscopy is the phenomenon of attracting and holding water molecules via either absorption or adsorption from the surrounding environment, which is usually at normal or room temperature. If water molecules become suspended among the substance ...

, glue-like substance called

viscin {{Short pages monitor A standardized system called the Hawksworth 6-class dwarf mistletoe rating (DMR) system has been devised to determine how much dwarf mistletoe has infected a tree. To use this system, the living part of the

tree crown The crown of a plant refers to the total of an individual plant's aboveground parts, including stems, leaves, and reproductive structures. A plant community canopy consists of one or more plant crowns growing in a given area. The crown of a w ...

needs to be broken up into 3 sections, (top, middle, bottom). Each section is then rated either 0, 1, or 2 with a score of 0 being assigned for a uninfected section, 1 for light infection with fewer than half of the branches infected, or 2 for heavy infection with over half of the branches infected. The 3 numbers are then added together to give the total rating for the tree.

Species

Arceuthobium occidentale on Pinus sabiniana

* ''

Arceuthobium abietinum ''Arceuthobium abietinum'' is a species of dwarf mistletoe known as fir dwarf mistletoe. It is native to western North America from Washington to New Mexico to northern Mexico, where it lives in coniferous forests as a parasite on various species ...

'' Engelm. ex Munz * '' Arceuthobium americanum'' Nutt. ex Engelm. * ''

Arceuthobium apachecum ''Arceuthobium apachecum'', called the "Apache dwarf mistletoe," is a parasitic plant found on the branches of pine trees in Arizona, New Mexico and Coahuila Coahuila (), formally Coahuila de Zaragoza (), officially the Free and Sovereign ...

'' Hawksworth & Wiens * '' Arceuthobium azoricum'' Hawksw. & Wiens * ''

Arceuthobium blumeri 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 ...

'' A. Nels. * ''

Arceuthobium californicum 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 ...

'' Hawksworth & Wiens * '' Arceuthobium campylopodum'' Engelm. * ''

Arceuthobium cyanocarpum 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 h ...

'' (A. Nels. ex Rydb.) A. Nels. * '' Arceuthobium divaricatum'' Engelm. * ''

Arceuthobium douglasii ''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 ...

'' Engelm. * ''

Arceuthobium gillii ''Arceuthobium gillii'', common name "Chihuahua pine dwarf mistletoe," is a parasitic plant found in Arizona, New Mexico, Chihuahua, Sonora and Sinaloa. It is found mostly on the Chihuahua pine ''Pinus leiophylla'', commonly known as Chihuah ...

'' Hawksworth & Wiens * '' Arceuthobium globosum'' Hawksw. & Wiens * ''

Arceuthobium laricis 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 ...

'' (Piper) St. John * ''

Arceuthobium littorum ''Arceuthobium littorum'' is a species of Arceuthobium, dwarf mistletoe known as coastal dwarf mistletoe. It is Endemism, endemic to the coastline of northern California, where it lives as a parasitic plant, parasite on Bishop Pine and Monterey P ...

'' Hawksworth, Wiens & Nickrent * ''

Arceuthobium microcarpum ''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 (''Picea'' spp.) but also occasionally on Rocky Mountain bristlecone pine ...

'' (Engelm.) Hawksworth & Wiens * '' Arceuthobium minutissimum'' Hook. f. * ''

Arceuthobium monticola ''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 tr ...

'' Hawksworth, Wiens & Nickrent * ''

Arceuthobium occidentale 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 ...

'' Engelm. * '' Arceuthobium oxycedri'' (DC.) M.Bieb. * ''

Arceuthobium pusillum ''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 t ...

'' Peck * ''

Arceuthobium siskiyouense ''Arceuthobium siskiyouense'' is a species of Arceuthobium, dwarf mistletoe known as knobcone pine dwarf mistletoe. It is Endemism, endemic to the Klamath Mountains of northern California and southern Oregon, where it lives as a parasitic plant, ...

'' Hawksworth, Wiens & Nickrent * '' Arceuthobium tsugense'' (Rosendahl) G.N. Jones * '' Arceuthobium vaginatum'' (Humb. & Bonpl. ex Willd.) J. Presl (Syn. ''Viscum vaginatum'' Humb. & Bonpl. ex Willd.)

References

External links

Maleshoots of ''A. campylopodum'' in California

Fruiting plant of ''A. campylopodum'' on Pine shoot

PLANTS profile for Arceuthobium (United States) including range maps.

US forest service data about dwarf mistletoes
{{Taxonbar, from=Q244255 Dioecious plants Epiphytes Parasitic plants Santalales genera

Description

Species

References

Further reading

External links