The Brassicales are an order of flowering plants, belonging to the eurosids II group of dicotyledons under the APG II system. One character common to many members of the order is the production of glucosinolate compounds. Most systems of classification have included this order, although sometimes under the name Capparales; the order contains the following families: Akaniaceae - two species of turnipwood trees, native to Asia and eastern Australia Bataceae – salt-tolerant shrubs from America and Australasia Brassicaceae – mustard and cabbage family. The only families included were the Brassicaceae and Capparaceae, the Tovariaceae and Moringaceae. Other taxa now included; the families Capparaceae and Brassicaceae are related. One group, consisting of Cleome and related genera, was traditionally included in the Capparaceae but doing so results in a paraphyletic Capparaceae. Therefore, this group is now either included in the Brassicaceae or as its own family, Cleomaceae. Media related to Brassicales at Wikimedia Commons
A leaf is an organ of a vascular plant and is the principal lateral appendage of the stem. The leaves and stem together form the shoot. Leaves are collectively referred to as foliage, as in "autumn foliage". A leaf is a thin, dorsiventrally flattened organ borne above ground and specialized for photosynthesis. In most leaves, the primary photosynthetic tissue, the palisade mesophyll, is located on the upper side of the blade or lamina of the leaf but in some species, including the mature foliage of Eucalyptus, palisade mesophyll is present on both sides and the leaves are said to be isobilateral. Most leaves have distinct upper surface and lower surface that differ in colour, the number of stomata, the amount and structure of epicuticular wax and other features. Leaves can have many different shapes and textures; the broad, flat leaves with complex venation of flowering plants are known as megaphylls and the species that bear them, the majority, as broad-leaved or megaphyllous plants. In the clubmosses, with different evolutionary origins, the leaves are simple and are known as microphylls.
Some leaves, such as bulb scales, are not above ground. In many aquatic species the leaves are submerged in water. Succulent plants have thick juicy leaves, but some leaves are without major photosynthetic function and may be dead at maturity, as in some cataphylls and spines. Furthermore, several kinds of leaf-like structures found in vascular plants are not homologous with them. Examples include flattened plant stems called phylloclades and cladodes, flattened leaf stems called phyllodes which differ from leaves both in their structure and origin; some structures of non-vascular plants function much like leaves. Examples include the phyllids of liverworts. Leaves are the most important organs of most vascular plants. Green plants are autotrophic, meaning that they do not obtain food from other living things but instead create their own food by photosynthesis, they capture the energy in sunlight and use it to make simple sugars, such as glucose and sucrose, from carbon dioxide and water. The sugars are stored as starch, further processed by chemical synthesis into more complex organic molecules such as proteins or cellulose, the basic structural material in plant cell walls, or metabolised by cellular respiration to provide chemical energy to run cellular processes.
The leaves draw water from the ground in the transpiration stream through a vascular conducting system known as xylem and obtain carbon dioxide from the atmosphere by diffusion through openings called stomata in the outer covering layer of the leaf, while leaves are orientated to maximise their exposure to sunlight. Once sugar has been synthesized, it needs to be transported to areas of active growth such as the plant shoots and roots. Vascular plants transport sucrose in a special tissue called the phloem; the phloem and xylem are parallel to each other but the transport of materials is in opposite directions. Within the leaf these vascular systems branch to form veins which supply as much of the leaf as possible, ensuring that cells carrying out photosynthesis are close to the transportation system. Leaves are broad and thin, thereby maximising the surface area directly exposed to light and enabling the light to penetrate the tissues and reach the chloroplasts, thus promoting photosynthesis.
They are arranged on the plant so as to expose their surfaces to light as efficiently as possible without shading each other, but there are many exceptions and complications. For instance plants adapted to windy conditions may have pendent leaves, such as in many willows and eucalyptss; the flat, or laminar, shape maximises thermal contact with the surrounding air, promoting cooling. Functionally, in addition to carrying out photosynthesis, the leaf is the principal site of transpiration, providing the energy required to draw the transpiration stream up from the roots, guttation. Many gymnosperms have thin needle-like or scale-like leaves that can be advantageous in cold climates with frequent snow and frost; these are interpreted as reduced from megaphyllous leaves of their Devonian ancestors. Some leaf forms are adapted to modulate the amount of light they absorb to avoid or mitigate excessive heat, ultraviolet damage, or desiccation, or to sacrifice light-absorption efficiency in favour of protection from herbivory.
For xerophytes the major constraint drought. Some window plants such as Fenestraria species and some Haworthia species such as Haworthia tesselata and Haworthia truncata are examples of xerophytes. and Bulbine mesembryanthemoides. Leaves function to store chemical energy and water and may become specialised organs serving other functions, such as tendrils of peas and other legumes, the protective spines of cacti and the insect traps in carnivorous plants such as Nepenthes and Sarracenia. Leaves are the fundamental structural units from which cones are constructed in gymnosperms and from which flowers are constructed in flowering plants; the internal organisation of most kinds of leaves has evolved to maximise exposure of the photosynthetic organelles, the chloroplasts, to light and to increase the absorption of carbon dioxide while at the same time controlling water loss. Their surfaces are waterproofed by the plant cuticle and gas exchange between the mesophyll cells and the atmosphere is controlled by minute openings called stomata which open or close to regulate the rate exchange of carbon dioxide and water vapour into
Ontario is one of the 13 provinces and territories of Canada and is located in east-central Canada. It is Canada's most populous province accounting for 38.3 percent of the country's population, is the second-largest province in total area. Ontario is fourth-largest jurisdiction in total area when the territories of the Northwest Territories and Nunavut are included, it is home to the nation's capital city and the nation's most populous city, Ontario's provincial capital. Ontario is bordered by the province of Manitoba to the west, Hudson Bay and James Bay to the north, Quebec to the east and northeast, to the south by the U. S. states of Minnesota, Ohio and New York. All of Ontario's 2,700 km border with the United States follows inland waterways: from the west at Lake of the Woods, eastward along the major rivers and lakes of the Great Lakes/Saint Lawrence River drainage system; these are the Rainy River, the Pigeon River, Lake Superior, the St. Marys River, Lake Huron, the St. Clair River, Lake St. Clair, the Detroit River, Lake Erie, the Niagara River, Lake Ontario and along the St. Lawrence River from Kingston, Ontario, to the Quebec boundary just east of Cornwall, Ontario.
There is only about 1 km of land border made up of portages including Height of Land Portage on the Minnesota border. Ontario is sometimes conceptually divided into Northern Ontario and Southern Ontario; the great majority of Ontario's population and arable land is in the south. In contrast, the larger, northern part of Ontario is sparsely populated with cold winters and heavy forestation; the province is named after Lake Ontario, a term thought to be derived from Ontarí:io, a Huron word meaning "great lake", or skanadario, which means "beautiful water" in the Iroquoian languages. Ontario has about 250,000 freshwater lakes; the province consists of three main geographical regions: The thinly populated Canadian Shield in the northwestern and central portions, which comprises over half the land area of Ontario. Although this area does not support agriculture, it is rich in minerals and in part covered by the Central and Midwestern Canadian Shield forests, studded with lakes and rivers. Northern Ontario is subdivided into two sub-regions: Northeastern Ontario.
The unpopulated Hudson Bay Lowlands in the extreme north and northeast swampy and sparsely forested. Southern Ontario, further sub-divided into four regions. Despite the absence of any mountainous terrain in the province, there are large areas of uplands within the Canadian Shield which traverses the province from northwest to southeast and above the Niagara Escarpment which crosses the south; the highest point is Ishpatina Ridge at 693 metres above sea level in Temagami, Northeastern Ontario. In the south, elevations of over 500 m are surpassed near Collingwood, above the Blue Mountains in the Dundalk Highlands and in hilltops near the Madawaska River in Renfrew County; the Carolinian forest zone covers most of the southwestern region of the province. The temperate and fertile Great Lakes-Saint Lawrence Valley in the south is part of the Eastern Great Lakes lowland forests ecoregion where the forest has now been replaced by agriculture and urban development. A well-known geographic feature is part of the Niagara Escarpment.
The Saint Lawrence Seaway allows navigation to and from the Atlantic Ocean as far inland as Thunder Bay in Northwestern Ontario. Northern Ontario occupies 87 percent of the surface area of the province. Point Pelee is a peninsula of Lake Erie in southwestern Ontario, the southernmost extent of Canada's mainland. Pelee Island and Middle Island in Lake Erie extend farther. All are south of 42°N – farther south than the northern border of California; the climate of Ontario varies by location. It is affected by three air sources: cold, arctic air from the north; the effects of these major air masses on temperature and precipitation depend on latitude, proximity to major bodies of water and to a small extent, terrain relief. In general, most of Ontario's climate is classified as humid continental. Ontario has three main climatic regions; the surrounding Great Lakes influence the climatic region of southern Ontario. During the fall and winter months, heat stored from the lakes is released, moderating the climate near the shores of the lakes.
This gives some parts of southern Ontario milder winters than mid-continental areas at lower latitudes. Parts of Southwestern Ontario have a moderate humid continental climate, similar to that of the inland Mid-Atlantic states and the Great Lakes portion of the Midwestern United States; the region has warm to cold winters. Annual precipitation is well distributed throughout the year. Most of this region lies in the lee of the Great Lakes. In December 2010, the snowbelt set a new record when it was h
Traditional medicine comprises medical aspects of traditional knowledge that developed over generations within various societies before the era of modern medicine. The World Health Organization defines traditional medicine as "the sum total of the knowledge and practices based on the theories and experiences indigenous to different cultures, whether explicable or not, used in the maintenance of health as well as in the prevention, improvement or treatment of physical and mental illness". Traditional medicine is contrasted with scientific medicine. In some Asian and African countries, up to 80% of the population relies on traditional medicine for their primary health care needs; when adopted outside its traditional culture, traditional medicine is considered a form of alternative medicine. Practices known as traditional medicines include traditional European medicine, traditional Chinese medicine, traditional Korean medicine, traditional African medicine, Siddha medicine, ancient Iranian Medicine, Islamic medicine, Ifá.
Scientific disciplines which study traditional medicine include herbalism, ethnomedicine and medical anthropology. The WHO notes, that "inappropriate use of traditional medicines or practices can have negative or dangerous effects" and that "further research is needed to ascertain the efficacy and safety" of several of the practices and medicinal plants used by traditional medicine systems; the World Health Organization has implemented a nine year strategy to "support Member States in developing proactive policies and implementing action plans that will strengthen the role traditional medicine plays in keeping populations healthy." In the written record, the study of herbs dates back 5,000 years to the ancient Sumerians, who described well-established medicinal uses for plants. In Ancient Egyptian medicine, the Ebers papyrus from c. 1552 BC records a list of folk remedies and magical medical practices. The Old Testament mentions herb use and cultivation in regards to Kashrut. Many herbs and minerals used in Ayurveda were described by ancient Indian herbalists such as Charaka and Sushruta during the 1st millennium BC.
The first Chinese herbal book was the Shennong Bencao Jing, compiled during the Han Dynasty but dating back to a much earlier date, augmented as the Yaoxing Lun during the Tang Dynasty. Early recognised Greek compilers of existing and current herbal knowledge include Pythagoras and his followers, Aristotle, Theophrastus and Galen. Roman sources included Pliny the Elder's Natural History and Celsus's De Medicina. Pedanius Dioscorides drew on and corrected earlier authors for his De Materia Medica, adding much new material. Latin manuscripts of De Materia Medica were combined with a Latin herbal by Apuleius Platonicus and were incorporated into the Anglo-Saxon codex Cotton Vitellius C. III; these early Greek and Roman compilations became the backbone of European medical theory and were translated by the Persian Avicenna, the Persian Rhazes and the Jewish Maimonides. Some fossils have been used in traditional medicine since antiquity. Arabic indigenous medicine developed from the conflict between the magic-based medicine of the Bedouins and the Arabic translations of the Hellenic and Ayurvedic medical traditions.
Spanish indigenous medicine was influenced by the Arabs from 711 to 1492. Islamic physicians and Muslim botanists such as al-Dinawari and Ibn al-Baitar expanded on the earlier knowledge of materia medica; the most famous Persian medical treatise was Avicenna's The Canon of Medicine, an early pharmacopoeia and introduced clinical trials. The Canon was translated into Latin in the 12th century and remained a medical authority in Europe until the 17th century; the Unani system of traditional medicine is based on the Canon. Translations of the early Roman-Greek compilations were made into German by Hieronymus Bock whose herbal, published in 1546, was called Kreuter Buch; the book was translated into Dutch as Pemptades by Rembert Dodoens, from Dutch into English by Carolus Clusius, published by Henry Lyte in 1578 as A Nievve Herball. This became John Gerard's General Hiftorie of Plantes; each new work was a compilation of existing texts with new additions. Women's folk knowledge existed in undocumented parallel with these texts.
Forty-four drugs, flavouring agents and emollients mentioned by Dioscorides are still listed in the official pharmacopoeias of Europe. The Puritans took Gerard's work to the United States where it influenced American Indigenous medicine. Francisco Hernández, physician to Philip II of Spain spent the years 1571–1577 gathering information in Mexico and wrote Rerum Medicarum Novae Hispaniae Thesaurus, many versions of which have been published including one by Francisco Ximénez. Both Hernandez and Ximenez fitted Aztec ethnomedicinal information into the European concepts of disease such as "warm", "cold", "moist", but it is not clear that the Aztecs used these categories. Juan de Esteyneffer's Florilegio medicinal de todas las enfermedas compiled European texts and added 35 Mexican plants. Martín de la Cruz wrote an herbal in Nahuatl, translated into Latin by Juan Badiano as Libellus de Medicinalibus Indorum Herbis or Codex Barberini, Latin 241 and given to King Carlos V of Spain in 1552, it was written in haste and influenced by the European occupation of the previous 30 year
Texas is the second largest state in the United States by both area and population. Geographically located in the South Central region of the country, Texas shares borders with the U. S. states of Louisiana to the east, Arkansas to the northeast, Oklahoma to the north, New Mexico to the west, the Mexican states of Chihuahua, Nuevo León, Tamaulipas to the southwest, while the Gulf of Mexico is to the southeast. Houston is the most populous city in Texas and the fourth largest in the U. S. while San Antonio is the second-most populous in the state and seventh largest in the U. S. Dallas–Fort Worth and Greater Houston are the fourth and fifth largest metropolitan statistical areas in the country, respectively. Other major cities include Austin, the second-most populous state capital in the U. S. and El Paso. Texas is nicknamed "The Lone Star State" to signify its former status as an independent republic, as a reminder of the state's struggle for independence from Mexico; the "Lone Star" can be found on the Texan state seal.
The origin of Texas's name is from the word taysha. Due to its size and geologic features such as the Balcones Fault, Texas contains diverse landscapes common to both the U. S. Southern and Southwestern regions. Although Texas is popularly associated with the U. S. southwestern deserts, less than 10% of Texas's land area is desert. Most of the population centers are in areas of former prairies, grasslands and the coastline. Traveling from east to west, one can observe terrain that ranges from coastal swamps and piney woods, to rolling plains and rugged hills, the desert and mountains of the Big Bend; the term "six flags over Texas" refers to several nations. Spain was the first European country to claim the area of Texas. France held a short-lived colony. Mexico controlled the territory until 1836 when Texas won its independence, becoming an independent Republic. In 1845, Texas joined the union as the 28th state; the state's annexation set off a chain of events that led to the Mexican–American War in 1846.
A slave state before the American Civil War, Texas declared its secession from the U. S. in early 1861, joined the Confederate States of America on March 2nd of the same year. After the Civil War and the restoration of its representation in the federal government, Texas entered a long period of economic stagnation. Four major industries shaped the Texas economy prior to World War II: cattle and bison, cotton and oil. Before and after the U. S. Civil War the cattle industry, which Texas came to dominate, was a major economic driver for the state, thus creating the traditional image of the Texas cowboy. In the 19th century cotton and lumber grew to be major industries as the cattle industry became less lucrative, it was though, the discovery of major petroleum deposits that initiated an economic boom which became the driving force behind the economy for much of the 20th century. With strong investments in universities, Texas developed a diversified economy and high tech industry in the mid-20th century.
As of 2015, it is second on the list of the most Fortune 500 companies with 54. With a growing base of industry, the state leads in many industries, including agriculture, energy and electronics, biomedical sciences. Texas has led the U. S. in state export revenue since 2002, has the second-highest gross state product. If Texas were a sovereign state, it would be the 10th largest economy in the world; the name Texas, based on the Caddo word táyshaʼ "friend", was applied, in the spelling Tejas or Texas, by the Spanish to the Caddo themselves the Hasinai Confederacy, the final -s representing the Spanish plural. The Mission San Francisco de los Tejas was completed near the Hasinai village of Nabedaches in May 1690, in what is now Houston County, East Texas. During Spanish colonial rule, in the 18th century, the area was known as Nuevo Reino de Filipinas "New Kingdom of the Philippines", or as provincia de los Tejas "province of the Tejas" also provincia de Texas, "province of Texas", it was incorporated as provincia de Texas into the Mexican Empire in 1821, declared a republic in 1836.
The Royal Spanish Academy recognizes both spellings and Texas, as Spanish-language forms of the name of the U. S. State of Texas; the English pronunciation with /ks/ is unetymological, based in the value of the letter x in historical Spanish orthography. Alternative etymologies of the name advanced in the late 19th century connected the Spanish teja "rooftile", the plural tejas being used to designate indigenous Pueblo settlements. A 1760s map by Jacques-Nicolas Bellin shows a village named Teijas on Trinity River, close to the site of modern Crockett. Texas is the second-largest U. S. state, with an area of 268,820 square miles. Though 10% larger than France and twice as large as Germany or Japan, it ranks only 27th worldwide amongst country subdivisions by size. If it were an independent country, Texas would be the 40th largest behind Zambia. Texas is in the south central part of the United States of America. Three of its borders are defined by rivers; the Rio Grande forms a natural border with the Mexican states of Chihuahua, Nuevo León, Tamaulipas to the south.
The Red River forms a natural border with Arkansas to the north. The Sabine River forms a natural border with Louisiana to the east; the Texas Panhandle has an eastern border with Oklahoma at 100° W, a northern border with Oklahoma at 36°30' N and a western
In botany, a fruit is the seed-bearing structure in flowering plants formed from the ovary after flowering. Fruits are the means. Edible fruits, in particular, have propagated with the movements of humans and animals in a symbiotic relationship as a means for seed dispersal and nutrition. Accordingly, fruits account for a substantial fraction of the world's agricultural output, some have acquired extensive cultural and symbolic meanings. In common language usage, "fruit" means the fleshy seed-associated structures of a plant that are sweet or sour, edible in the raw state, such as apples, grapes, lemons and strawberries. On the other hand, in botanical usage, "fruit" includes many structures that are not called "fruits", such as bean pods, corn kernels and wheat grains; the section of a fungus that produces spores is called a fruiting body. Many common terms for seeds and fruit do not correspond to the botanical classifications. In culinary terminology, a fruit is any sweet-tasting plant part a botanical fruit.
However, in botany, a fruit is the ripened ovary or carpel that contains seeds, a nut is a type of fruit and not a seed, a seed is a ripened ovule. Examples of culinary "vegetables" and nuts that are botanically fruit include corn, eggplant, sweet pepper, tomato. In addition, some spices, such as allspice and chili pepper, are fruits. In contrast, rhubarb is referred to as a fruit, because it is used to make sweet desserts such as pies, though only the petiole of the rhubarb plant is edible, edible gymnosperm seeds are given fruit names, e.g. ginkgo nuts and pine nuts. Botanically, a cereal grain, such as corn, rice, or wheat, is a kind of fruit, termed a caryopsis. However, the fruit wall is thin and is fused to the seed coat, so all of the edible grain is a seed; the outer edible layer, is the pericarp, formed from the ovary and surrounding the seeds, although in some species other tissues contribute to or form the edible portion. The pericarp may be described in three layers from outer to inner, the epicarp and endocarp.
Fruit that bears a prominent pointed terminal projection is said to be beaked. A fruit results from maturation of one or more flowers, the gynoecium of the flower forms all or part of the fruit. Inside the ovary/ovaries are one or more ovules where the megagametophyte contains the egg cell. After double fertilization, these ovules will become seeds; the ovules are fertilized in a process that starts with pollination, which involves the movement of pollen from the stamens to the stigma of flowers. After pollination, a tube grows from the pollen through the stigma into the ovary to the ovule and two sperm are transferred from the pollen to the megagametophyte. Within the megagametophyte one of the two sperm unites with the egg, forming a zygote, the second sperm enters the central cell forming the endosperm mother cell, which completes the double fertilization process; the zygote will give rise to the embryo of the seed, the endosperm mother cell will give rise to endosperm, a nutritive tissue used by the embryo.
As the ovules develop into seeds, the ovary begins to ripen and the ovary wall, the pericarp, may become fleshy, or form a hard outer covering. In some multiseeded fruits, the extent to which the flesh develops is proportional to the number of fertilized ovules; the pericarp is differentiated into two or three distinct layers called the exocarp and endocarp. In some fruits simple fruits derived from an inferior ovary, other parts of the flower, fuse with the ovary and ripen with it. In other cases, the sepals, petals and/or stamens and style of the flower fall off; when such other floral parts are a significant part of the fruit, it is called an accessory fruit. Since other parts of the flower may contribute to the structure of the fruit, it is important to study flower structure to understand how a particular fruit forms. There are three general modes of fruit development: Apocarpous fruits develop from a single flower having one or more separate carpels, they are the simplest fruits. Syncarpous fruits develop from a single gynoecium having two or more carpels fused together.
Multiple fruits form from many different flowers. Plant scientists have grouped fruits into three main groups, simple fruits, aggregate fruits, composite or multiple fruits; the groupings are not evolutionarily relevant, since many diverse plant taxa may be in the same group, but reflect how the flower organs are arranged and how the fruits develop. Simple fruits can be either dry or fleshy, result from the ripening of a simple or compound ovary in a flower with only one pistil. Dry fruits may be either dehiscent, or indehiscent. Types of dry, simple fruits, examples of each, include: achene – most seen in aggregate fruits capsule – caryopsis – cypsela – an achene-like fruit derived from the individual florets in a capitulum. Fibrous drupe – follicle – is formed from a single carpel, opens by one suture
Artemisia tridentata called big sagebrush, Great Basin sagebrush or sagebrush, is an aromatic shrub from the family Asteraceae, which grows in arid and semi-arid conditions, throughout a range of cold desert and mountain habitats in the Intermountain West of North America. The vernacular name "sagebrush" is used for several related members of the genus Artemisia, such as California sagebrush. Big Sagebrush and other Artemisia shrubs are the dominant plant species across large portions of the Great Basin; the range extends northward through British Columbia's southern interior, south into Baja California, east into the western Great Plains of New Mexico, Colorado and the Dakotas. Several major threats exist to sage brush ecosystems, including human settlements, conversion to agricultural land, livestock grazing, invasive plant species and climate change. Sagebrush provides food and habitat for a variety of species, such as sage grouse, pronghorn antelope, grey vireo, pygmy rabbit, mule deer.
Artemisia tridentata is the state flower of Nevada. 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. A. tridentata subsp. Tridentata A. tridentata subsp. Vaseyana A. tridentata subsp. Wyomingensis – Found in the drier portions of the sagebrush steppe. Shrub density is less than 1 plant/m2, with little herbaceous cover surrounding the shrub. A. tridentata subsp. Xericensis A. tridentata subsp. Spiciformis A. tridentata subsp. Parishii – Big sagebrush is a coarse, many-branched, pale-grey shrub with yellow flowers and silvery-grey foliage, 0.5–3 m tall. A deep taproot 1–4 m 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, over a meter tall is an indicator of arable land, because it prefers deep, basic soils. Sagebrush is long-lived once it makes it past the seedling stage, can reach ages of over 100 years.
The species has a strong pungent fragrance due to the presence of camphor and other volatile oils. The taste is bitter and, together with the odor, serves to discourage browsing by many herbivores, it is an evergreen shrub. The leaves—attached to the branches at the axillary nodes—are wedge-shaped, 1–3 cm long and 0.3–1 cm broad, with the wider outer tips divided into three lobes. The leaves are covered with fine silvery hairs. Artemisia tridentata flowers in the late summer or early fall; the small yellow flowers are in long, loosely arranged tubular clusters. The fruits are seed-like, have a small amount of hairs on the surface; the Cahuilla used to gather large quantities of sagebrush seed, grind it to make flour. Big sagebrush can reproduce through sprouts, which shoot up from the underground rhizome; the sprouts are an extension of the parental plant while seedlings are individualistic to any other plant. Among these two strategies, the seedlings need more moisture for early survival; this is due to the sprouts being connected to healthy and associated plants while the new seedlings will start anew.
Artemisia tridentata grows in arid and semi-arid conditions, throughout the Intermountain West of North America. Sagebrush is not a desert plant, but rather a resident of the steppe, in areas that receive 18–40 centimeters of annual precipitation. Big sagebrush and other Artemisia species are the dominant plants across large portions of the Great Basin, covering some 422,000 square miles in 11 western U. S. states and Canadian provinces. Sagebrush provides food and habitat for a variety of animal species, such as sage grouse, grey vireo, pygmy rabbit, mule deer. Sagebrush 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; 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.
Pronghorn are the only large herbivore to browse sagebrush extensively. 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 60 cm. Several major threats exist to sage brush ecosystems, including human settlements, conversion to agricultural land, livestock grazing, invasive plant species and climate change; the cattle industry burns large areas of sagebrush habitat to make way for grazing animals. 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 detrimental to the ecosystem as a whole. 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