Artemisia tridentata
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Artemisia tridentata, commonly called big sagebrush,<ref name="MDW">MacKay, Pam (2013), Mojave Desert Wildflowers, 2nd ed., Template:ISBN, p. 264.</ref> Great Basin sagebrush<ref name=MDW/> or simply sagebrush (one of several related species of this name), is an aromatic shrub from the family Asteraceae.
It grows in arid and semi-arid conditions, throughout a range of cold desert, steppe, and mountain habitats in the Intermountain West of North America. Big sagebrush and other Artemisia shrubs are the dominant plant species across large portions of the Great Basin.
Sagebrush provides food and habitat for a variety of species, such as sage grouse, pronghorn antelope, grey vireo, pygmy rabbit, and mule deer. Several major threats exist to sagebrush ecosystems, including human settlements, conversion to agricultural land, invasive plant species, and wildfires.
Native Americans have used the plant medicinally. It is also useful as firewood.
DescriptionEdit
Big sagebrush is a coarse, many-branched, pale-grey shrub with yellow flowers and silvery-grey foliage, which is generally Template:Convert tall.<ref>Template:Cite book</ref> A deep taproot Template:Convert in length, coupled with laterally spreading roots near the surface, allows sagebrush to gather water from both surface precipitation and the water table several meters beneath. Big sagebrush that is over a meter tall is an indicator of arable land, because it prefers deep, basic soils.<ref name="Mozingo-1987-p271">Template:Cite book</ref> Sagebrush is generally long-lived once it makes it past the seedling stage, and can reach ages of over 100 years.<ref name="Barbour-2000-p259">Template:Cite book</ref>
The species has a strong pungent fragrance (especially when wet) due to the presence of camphor, terpenoids and other volatile oils.<ref name=shakhnoza>Template:Cite book</ref> The taste is bitter and, together with the odor, serves to discourage browsing by many herbivores. It is an evergreen shrub, keeping some of its leaves year-round (although it loses many of them in the late summer).<ref>Template:Cite book</ref> The leaves—attached to the branches at the axillary nodes—are wedge-shaped, Template:Convert long and 0.3–1 cm broad, with the wider outer tips divided into three lobes (hence the scientific name tridentata).<ref>Template:Cite book</ref><ref>Template:Cite book</ref><ref name="Clarke-1978-p134">Template:Cite book</ref> The leaves are covered with fine silvery hairs.<ref name="Kershaw-2001-p25">Template:Cite book</ref>
The plant flowers in the late summer or early fall.<ref>Template:Cite book</ref> The small yellow flowers are in long, loosely arranged tubular clusters.<ref>Template:Cite book</ref> The fruits are seed-like and have a small amount of hairs on the surface.<ref name="Kershaw-2001-p25" />
Big sagebrush can also reproduce through sprouts, which shoot up from the underground rhizome. The sprouts are an extension of the parental plant while seedlings are completely individualistic to any other plant. Among these two strategies, the seedlings need more moisture for germination and early survival. This is due to the sprouts being connected to already healthy and associated plants while the new seedlings will start anew.Template:Citation needed
ChemistryEdit
Sagebrush essential oil contains approximately 40% l-camphor; 20% pinene; 7% cineole; 5% methacrolein; and 12% a-terpinene, d-camphor, and sesqiterpenoids.<ref name="shakhnoza" />
TaxonomyEdit
Much discussion and disagreement revolves around the question of how to divide the species into varieties and subgenera. The following subspecies are accepted by some authors, though others advocate different systems.<ref name="Barbour-2000-p259" /><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
- A. tridentata subsp. tridentata ("basin big sagebrush")
- A. tridentata subsp. vaseyana ("mountain big sagebrush")
- A. tridentata subsp. wyomingensis ("Wyoming big sagebrush") – Found in the drier portions of the sagebrush steppe. Shrub density is generally less than 1 plant/m2, with little herbaceous cover surrounding the shrub.<ref>Template:Cite book</ref>
- A. tridentata subsp. xericensis ("scabland big sagebrush")
- A. tridentata subsp. spiciformis ("subalpine big sagebrush")
- A. tridentata subsp. parishii ("Parish's big sagebrush")
Distribution and habitatEdit
Artemisia tridentata grows in arid and semi-arid conditions, throughout the Intermountain West of North America.<ref>Template:Cite book</ref> Sagebrush is not a desert plant, but rather a resident of the steppe, in areas that receive Template:Convert of annual precipitation.<ref>Template:Cite book</ref> Big sagebrush and other Artemisia species are the dominant plants across large portions of the Great Basin, covering some Template:Convert in 11 western U.S. states and Canadian provinces.<ref>Template:Cite book</ref> The range extends northward through British Columbia's southern interior, south into Baja California, and east into the western Great Plains of New Mexico, Colorado, Nebraska, and the Dakotas.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
EcologyEdit
Sagebrush provides food and habitat for a variety of animal species, such as sage grouse, pronghorn, gray vireo, pygmy rabbit, and mule deer.<ref>Template:Cite book</ref><ref>Template:Cite book</ref> It is especially important to game animals during the winter.<ref name="Knopf">Template:Cite book</ref> Sagebrush also creates habitat for many species of grasses and herbs. Besides providing shade and shelter from the wind, the long taproot of sagebrush draws water up from deep in the soil, some of which becomes available to these surrounding shallow-rooted plants.<ref>Template:Cite book</ref>
The terpenoid compounds in big sagebrush are thought to ward off herbivores. These oils, at high concentrations, are toxic to the symbiotic bacteria in the rumen of some ruminants like deer and cattle.<ref>Nagy, JG and RP Tengerdy. 1968. Antibacterial action of essential oils of Artemisia as an ecological factor: II. Antibacterial action of the volatile oils of Artemisia tridentata (big sagebrush) on bacteria from the rumen of mule deer" Applied and Environmental Microbiology 16(3) 441–44.</ref><ref>Template:Cite book</ref> Pronghorn are the only large herbivore to browse sagebrush extensively.<ref>Template:Cite book</ref> Damage to sagebrush plants caused by grazing herbivores results in the release of volatile chemicals, which are used to signal a warning to nearby plants, so that they can increase the production of repellent chemical compounds. This plant-to-plant communication can take place at distances of up to Template:Convert.<ref>Template:Cite book</ref>
Several major threats exist to sage brush ecosystems, including human settlements, conversion to agricultural land, invasive plant species, wildfires, and climate change.<ref>Template:Cite book</ref><ref>Template:Cite book</ref> Due to large periods of time where sagebrush was the primary shrub, many species have become adapted to this habitat. The burning of the shrubs leads to habitat loss of many species and can be very detrimental to the ecosystem as a whole.<ref>Template:Cite journal</ref> Furthermore, the destruction of native grasses and forbs by grazing and fire creates conditions where invasive plants colonize the area. The invasive species which has destroyed the largest amount of sagebrush habitat is cheatgrass (Bromus tectorum). Since its accidental introduction in the 1890s,<ref>Template:Cite book</ref> cheatgrass has radically altered the native shrub ecosystem by replacing indigenous vegetation,<ref name="Radosevich-2007-p26">Template:Cite book</ref> and by creating a fire cycle that is too frequent to allow sagebrush to re-establish itself. Sagebrush lacks fire tolerance and relies on wind-blown seeds from outside the burned area for re-establishment.<ref>This is in contrast to many of the other plants which share its habitat, such as Rabbitbrush, Ephedra and bunchgrasses, which can root-sprout after a fire.</ref><ref>Template:Cite book</ref> Some tree species have also encroached on big sagebrush habitat. For example, in the late 20th century, Abies concolor (white fir) was out-competing big sagebrush in Warner Mountains in California.<ref>Template:Cite journal</ref>
GallsEdit
This species is host to the following insect induced galls:
- Eutreta diana fly bud gall
- Eutreta divisa fly bud gall
- Eutreta oregona fly bud gall
- Eutreta pollinosa fly bud? gall
- Oxyna aterrima fly bud gall
- Rhopalomyia (ampullaria, anthoides, brevibulla,calvipomum, conica, cramboides,culmata, florella, gossypina, hirticaulis, hirtipomum, lignea, lignitubus, mammilla, medusa, medusirrasa, nucula, obovata, occidentalis, pomum, rugosa, tridentatae, tubulus, tumidibulla, tumidicaulis) Various gall midges.
- Eutreta diana 1.jpg
Eutreta diana
- Rhopalomyia calvipomum.jpg
Rhopalomyia calvipomum
- Rhopalomyia conica 1.jpg
Rhopalomyia conica
- Rhopalomyia pomum gall.jpg
Rhopalomyia pomum
- Rhopalomyia medusa 1.jpg
Rhopalomyia medusa
UsesEdit
The Cahuilla used to gather large quantities of sagebrush seed and grind it to make flour.<ref name="Clarke-1978-p134" /><ref>Template:Cite book</ref> The main modern use is as firewood, with the wood's oils being particularly flammable.<ref name="Knopf" />
MedicinalEdit
The plant's active medicinal constituents include camphor, terpenoids, and tannins.<ref name="shakhnoza" />
It is used as a herbal medicine by Native Americans throughout the Intermountain West of North America, most notably as a smudging herb. It is also used for preventing infection in wounds, stopping internal bleeding, and treating headaches and colds.
The Navajo use the vapors of sagebrush as a treatment for headache.<ref name="Tilford">Edible and Medicinal Plants of the West, Gregory L. Tilford, Template:ISBN Template:Page needed</ref><ref>Template:Cite book</ref> The Okanagan and Colville people used sagebrush to smoke hides.<ref>Template:Cite book</ref>
Among the Zuni people, an infusion of the leaves is used externally for body aches. The infusion is also taken as a cold medicine. It is also placed in shoes to treat athlete's foot, fissures between toes, and as a foot deodorant.<ref>Camazine, Scott and Robert A. Bye 1980 A Study Of The Medical Ethnobotany Of The Zuni Indians of New Mexico" Journal of Ethnopharmacology 2:365–88 (p. 374)</ref>
CultureEdit
Artemisia tridentata is the state flower of Nevada.