In biology, a hybrid is the offspring resulting from combining the qualities of two organisms of different breeds, species or genera through sexual reproduction. Hybrids are not always intermediates between their parents, but can show hybrid vigour, sometimes growing larger or taller than either parent; the concept of a hybrid is interpreted differently in animal and plant breeding, where there is interest in the individual parentage. In genetics, attention is focused on the numbers of chromosomes. In taxonomy, a key question is how related the parent species are. Species are reproductively isolated by strong barriers to hybridisation, which include morphological differences, differing times of fertility, mating behaviors and cues, physiological rejection of sperm cells or the developing embryo; some act before fertilization and others after it. Similar barriers exist in plants, with differences in flowering times, pollen vectors, inhibition of pollen tube growth, somatoplastic sterility, cytoplasmic-genic male sterility and the structure of the chromosomes.
A few animal species and many plant species, are the result of hybrid speciation, including important crop plants such as wheat, where the number of chromosomes has been doubled. Human impact on the environment has resulted in an increase in the interbreeding between regional species, the proliferation of introduced species worldwide has resulted in an increase in hybridisation; this genetic mixing may threaten many species with extinction, while genetic erosion in crop plants may be damaging the gene pools of many species for future breeding. A form of intentional human-mediated hybridisation is the crossing of wild and domesticated species; this is common in modern agriculture. One such flower, Oenothera lamarckiana, was central to early genetics research into mutationism and polyploidy, it is more done in the livestock and pet trades. Human selective breeding of domesticated animals and plants has resulted is the development of distinct breeds. Hybrid humans existed in prehistory. For example and anatomically modern humans are thought to have interbred as as 40,000 years ago.
Mythological hybrids appear in human culture in forms as diverse as the Minotaur, blends of animals and mythical beasts such as centaurs and sphinxes, the Nephilim of the Biblical apocrypha described as the wicked sons of fallen angels and attractive women. The term hybrid is derived from Latin hybrida, used for crosses such as of a tame sow and a wild boar; the term came into popular use in English in the 19th century, though examples of its use have been found from the early 17th century. Conspicuous hybrids are popularly named with portmanteau words, starting in the 1920s with the breeding of tiger–lion hybrids. From the point of view of animal and plant breeders, there are several kinds of hybrid formed from crosses within a species, such as between different breeds. Single cross hybrids result from the cross between two true-breeding organisms which produces an F1 hybrid; the cross between two different homozygous lines produces an F1 hybrid, heterozygous. The F1 generation is phenotypically homogeneous, producing offspring that are all similar to each other.
Double cross hybrids result from the cross between two different F1 hybrids. Three-way cross hybrids result from the cross between an inbred line. Triple cross hybrids result from the crossing of two different three-way cross hybrids. Top cross hybrids result from the crossing of a top quality or pure-bred male and a lower quality female, intended to improve the quality of the offspring, on average. Population hybrids result from the crossing of plants or animals in one population with those of another population; these crosses between different breeds. In horticulture, the term stable hybrid is used to describe an annual plant that, if grown and bred in a small monoculture free of external pollen produces offspring that are "true to type" with respect to phenotype. Hybridisation can occur in the hybrid zones where the geographical ranges of species, subspecies, or distinct genetic lineages overlap. For example, the butterfly Limenitis arthemis has two major subspecies in North America, L. a. arthemis and L. a. astyanax.
The white admiral has a bright, white band on its wings, while the red-spotted purple has cooler blue-green shades. Hybridisation occurs between a narrow area across New England, southern Ontario, the Great Lakes, the "suture region", it is at these regions. Other hybrid zones have formed between described species of animals. From the point of view of genetics, several different kinds of hybrid can be distinguished. A genetic hybrid carries two different alleles of the same gene, where for instance one allele may code for a lighter coat colour than the other. A structural hybrid results from the fusion of gametes that have differing structure in at least one chromosome, as a result of structural abnormalities. A numerical hybrid results from the fusion of gamet
Northeastern United States
The Northeastern United States referred to as the Northeast, is a geographical region of the United States bordered to the north by Canada, to the east by the Atlantic Ocean, to the south by the Southern United States, to the west by the Midwestern United States. The Northeast is one of the four regions defined by the United States Census Bureau for the collection and analysis of statistics; the Census Bureau-defined region has a total area of 181,324 sq mi with 162,257 sq mi of that being land mass. Although it lacks a unified cultural identity, the Northeastern region is the nation's most economically developed, densely populated, culturally diverse region. Of the nation's four census regions, the Northeast is the second most urban, with 85 percent of its population residing in urban areas, led by the West with 90 percent. Geographically there has always been some debate as to where the Northeastern United States begins and ends; the vast area from central Virginia to northern Maine, from western Pennsylvania to the Atlantic Ocean, have all been loosely grouped into the Northeast at one time or another.
Much of the debate has been what the cultural and urban aspects of the Northeast are, where they begin or end as one reaches the borders of the region. Using the Census Bureaus definition of the northeast, the region includes nine states: they are Maine, New York, New Jersey, Massachusetts, Rhode Island, New Hampshire, Pennsylvania; the region is subdivided into New England and the Mid-Atlantic states. This definition has been unchanged since 1880 and is used as a standard for data tabulation. However, the Census Bureau has acknowledged the obvious limitations of this definition and the potential merits of a proposal created after the 1950 census that would include changing regional boundaries to include Delaware and the District of Columbia, with the Mid-Atlantic states, but decided that "the new system did not win enough overall acceptance among data users to warrant adoption as an official new set of general-purpose State groupings; the previous development of many series of statistics and issued over long periods of time on the basis of the existing State groupings, favored the retention of the summary units of the current regions and divisions."
The Census Bureau confirmed in 1994 that it would continue to "review the components of the regions and divisions to ensure that they continue to represent the most useful combinations of States and State equivalents."Many organizations and reference works follow the Census Bureau's definition for the region. The Association of American Geographers divides the Northeast into two divisions: "New England", which consists of Maine, New Hampshire, Rhode Island, Connecticut; the Geological Society of America defines the Northeast as these same states but with the addition of Maryland and the District of Columbia. The narrowest definitions include only the states of New England. Other more restrictive definitions include New England and New York as part of the Northeast United States, but exclude Pennsylvania and New Jersey. States beyond the Census Bureau definition are included in Northeast Region by various other entities: Various organizations include: Delaware and District of Columbia; the US EPA and NOAA include in their Northeast Region: Delaware and West Virginia.
The National Fish and Wildlife Service includes in their Northeast Region: Delaware, District of Columbia, West Virginia, Virginia. The National Park Service includes in their Northeast Region: Delaware, West Virginia, Virginia. Anthropologists recognize the "Northeastern Woodlands" as one of the cultural regions that existed in the Western Hemisphere at the time of European colonists in the 15th and centuries. Most did not settle in North America until the 17th century; the cultural area, known as the "Northeastern Woodlands", in addition to covering the entire Northeast U. S. covered much of what is now Canada and others regions of what is now the eastern United States. Among the many tribes that inhabited this area were those that made up the Iroquois nations and the numerous Algonquian peoples. In the United States of the 21st century, 18 federally recognized tribes reside in the Northeast. For the most part, the people of the Northeastern Woodlands, on whose lands European fishermen began camping to dry their codfish in the early 1600s, lived in villages after being influenced by the agricultural traditions of the Ohio and Mississippi valley societies.
All of the states making up the Northeastern region were among the original Thirteen Colonies, though Maine and Delaware were part of other colonies before the United States became independent in the American Revolution. The two cultural and geographic regions that form parts of the Northeastern region have distinct histories; the first Europeans to settle New England were Pilgrims from England, who landed in present-day Massachusetts in 1620. The Pilgrims arrived by the Mayflower ship and founded Plymouth Colony so they could practice religion freely. Ten years a larger group of Puritans settled north of Plymouth Colony in Boston to form Massachusetts Bay Colony. In 1636, colonists established Providence Plantations. Providence was founded by Roger Williams, banished
Sichuan, is a province in southwest China occupying most of the Sichuan Basin and the easternmost part of the Tibetan Plateau between the Jinsha River on the west, the Daba Mountains in the north, the Yungui Plateau to the south. Sichuan's capital city is Chengdu; the population of Sichuan stands at 81 million. In antiquity, Sichuan was the home of the ancient states of Shu, their conquest by Qin strengthened it and paved the way for the Qin Shi Huang's unification of China under the Qin dynasty. During the Three Kingdoms era, Liu Bei's Shu was based in Sichuan; the area was devastated in the 17th century by Zhang Xianzhong's rebellion and the area's subsequent Manchu conquest, but recovered to become one of China's most productive areas by the 19th century. During the World War II, Chongqing served as the temporary capital of the Republic of China, making it the focus of Japanese bombing, it was one of the last mainland areas to fall to the Communists during the Chinese Civil War and was divided into four parts from 1949 to 1952, with Chongqing restored two years later.
It suffered gravely during the Great Chinese Famine of 1959–61 but remained China's most populous province until Chongqing Municipality was again separated from it in 1997. The people of Sichuan speak a unique form of Mandarin, which took shape during the area's repopulation under the Ming; the family of dialects is now spoken by about 120 million people, which would make it the 10th most spoken language in the world if counted separately. The area's warm damp climate long caused Chinese medicine to advocate spicy dishes. Many people believe that the name Sichuan means "four rivers", in folk etymology this is taken to mean the province's four major rivers: the Jialing, Jinsha and Tuo. According to historical geographer Tan Qixiang, "four rivers" is an erroneous interpretation of the place name; the name of the province is a contraction of the phrases Sì Chuānlù and Chuānxiá Sìlù, referring to the division of the existing imperial administrative circuit in the area into four during the Northern Song dynasty.
The character Chuan here means "plain" and not "river" as believed. In addition to its postal map and Wade-Giles forms, the name has been irregularly romanized as Szű-chuan and Szechuan. In antiquity, the area of modern Sichuan including the now separated Chongqing Municipality was known to the Chinese as Ba-Shu, in reference to the ancient states of Ba and Shu that once occupied the Sichuan Basin. Shu continued to be used to refer to the Sichuan region all through its history right up to the present day. Both the characters for Shu and Chuan are used as abbreviations for Sichuan; the Sichuan Basin and adjacent areas of the Yangtze watershed were a cradle of indigenous civilizations dating back to at least the 15th century BC, coinciding with the Shang in northern China. The region worldview; the earliest culture found in the region through archaeological investigation is the Baodun culture excavated in the Chengdu Plain. The most important native states were those of Shu. Ba stretched into Sichuan from the Han Valley in Shaanxi and Hubei down the Jialing River as far as its confluence with the Yangtze at Chongqing.
Shu occupied the valley of the Min, including other areas of western Sichuan. The existence of the early state of Shu was poorly recorded in the main historical records of China, it was, referred to in the Book of Documents as an ally of the Zhou. Accounts of Shu exist as a mixture of mythological stories and historical legends recorded in local annals such as the Chronicles of Huayang compiled in the Jin dynasty, the Han dynasty compilation Shuwang benji; these contained folk stories such as that of Emperor Duyu who taught the people agriculture and transformed himself into a cuckoo after his death. The existence of a developed civilization with an independent bronze industry in Sichuan came to light with an archaeological discovery in 1986 at a small village named Sanxingdui in Guanghan, Sichuan; this site, believed to be an ancient city of Shu, was discovered by a local farmer in 1929 who found jade and stone artefacts. Excavations by archaeologists in the area yielded few significant finds until 1986 when two major sacrificial pits were found with spectacular bronze items as well as artefacts in jade, gold and stone.
This and other discoveries in Sichuan contest the conventional historiography that the local culture and technology of Sichuan were undeveloped in comparison to the technologically and culturally "advanced" Yellow River valley of north-central China. The rulers of the expansionist state of Qin, based in present-day Gansu and Shaanxi, were the first strategists to realize that the area's military importance matched its commercial and agricultural significance; the Sichuan basin is surrounded by the Hengduan Mountains to the west, the Qin Mountains to the north, Yungui Plateau to the south. Since the Yangtze flows through the basin and through the perilous Three Gorges to eastern and southern China, Sichuan was a staging area for amphibious military forces and a haven for political refugees. Qin armies finished their conquest of the k
Tetraclinis is a genus of evergreen coniferous trees in the cypress family Cupressaceae, containing only one species, Tetraclinis articulata known as Thuja articulata, sandarac tree or Barbary thuja, endemic to the western Mediterranean region. It is native to northwestern Africa in the Atlas Mountains of Morocco and Tunisia, with two small outlying populations on Malta, near Cartagena in southeast Spain, it grows at low altitudes in a hot, dry subtropical Mediterranean climate. Its closest relatives are Platycladus and Calocedrus, with the closest resemblance to the latter. In older texts, it was sometimes treated in Thuja or Callitris, but it is less related to those genera, it is a small, slow-growing tree, to 6–15 m tall and 0.5 m trunk diameter with two or more trunks from the base. The foliage forms in open sprays with scale-like leaves 1 -- 1 -- 1.5 mm broad. The cones are 10–15 mm long, green ripening brown in about 8 months from pollination, have four thick scales arranged in two opposite pairs.
The seeds are 5 -- 2 mm broad, with a 3 -- 4 mm broad papery wing on each side. It is one of only a small number of conifers able to coppice, an adaptation to survive wildfire and moderate levels of browsing by animals. Old trees that have sprouted over a long period form large burls at the base, known as lupias, it is the national tree of Malta. It is now being used locally in afforestation projects; the resin, known as sandarac, is used to make lacquer. The wood, known as thuya wood or citron wood, also known as thyine wood, is used for decorative woodwork wood from burls at the base of the trunk; the market in Morocco is unsustainable, focusing as it does on the burl, has resulted in mass deforestation of the species. The species is threatened by overgrazing, which can kill the coppice regrowth before it gets tall enough to be out of the reach of livestock; the species is cultivated to be grown as an ornamental tree, valued in dry climates. It is pruned in a hedge form, for privacy and security.
The plant can be trained for use as bonsai specimens. †Tetraclinis salicornioides leaf and cone fossils of Messinian age have been uncovered in Monte Tondo and Borgo Tossignano, northern Apennines, Italy
California is a state in the Pacific Region of the United States. With 39.6 million residents, California is the most populous U. S. the third-largest by area. The state capital is Sacramento; the Greater Los Angeles Area and the San Francisco Bay Area are the nation's second and fifth most populous urban regions, with 18.7 million and 9.7 million residents respectively. Los Angeles is California's most populous city, the country's second most populous, after New York City. California has the nation's most populous county, Los Angeles County, its largest county by area, San Bernardino County; the City and County of San Francisco is both the country's second-most densely populated major city after New York City and the fifth-most densely populated county, behind only four of the five New York City boroughs. California's $3.0 trillion economy is larger than that of any other state, larger than those of Texas and Florida combined, the largest sub-national economy in the world. If it were a country, California would be the 5th largest economy in the world, the 36th most populous as of 2017.
The Greater Los Angeles Area and the San Francisco Bay Area are the nation's second- and third-largest urban economies, after the New York metropolitan area. The San Francisco Bay Area PSA had the nation's highest GDP per capita in 2017 among large PSAs, is home to three of the world's ten largest companies by market capitalization and four of the world's ten richest people. California is considered a global trendsetter in popular culture, innovation and politics, it is considered the origin of the American film industry, the hippie counterculture, fast food, the Internet, the personal computer, among others. The San Francisco Bay Area and the Greater Los Angeles Area are seen as global centers of the technology and entertainment industries, respectively. California has a diverse economy: 58% of the state's economy is centered on finance, real estate services and professional, scientific and technical business services. Although it accounts for only 1.5% of the state's economy, California's agriculture industry has the highest output of any U.
S. state. California is bordered by Oregon to the north and Arizona to the east, the Mexican state of Baja California to the south; the state's diverse geography ranges from the Pacific Coast in the west to the Sierra Nevada mountain range in the east, from the redwood–Douglas fir forests in the northwest to the Mojave Desert in the southeast. The Central Valley, a major agricultural area, dominates the state's center. Although California is well-known for its warm Mediterranean climate, the large size of the state results in climates that vary from moist temperate rainforest in the north to arid desert in the interior, as well as snowy alpine in the mountains. Over time and wildfires have become more pervasive features. What is now California was first settled by various Native Californian tribes before being explored by a number of European expeditions during the 16th and 17th centuries; the Spanish Empire claimed it as part of Alta California in their New Spain colony. The area became a part of Mexico in 1821 following its successful war for independence but was ceded to the United States in 1848 after the Mexican–American War.
The western portion of Alta California was organized and admitted as the 31st state on September 9, 1850. The California Gold Rush starting in 1848 led to dramatic social and demographic changes, with large-scale emigration from the east and abroad with an accompanying economic boom; the word California referred to the Baja California Peninsula of Mexico. The name derived from the mythical island California in the fictional story of Queen Calafia, as recorded in a 1510 work The Adventures of Esplandián by Garci Rodríguez de Montalvo; this work was the fifth in a popular Spanish chivalric romance series that began with Amadis de Gaula. Queen Calafia's kingdom was said to be a remote land rich in gold and pearls, inhabited by beautiful black women who wore gold armor and lived like Amazons, as well as griffins and other strange beasts. In the fictional paradise, the ruler Queen Calafia fought alongside Muslims and her name may have been chosen to echo the title of a Muslim leader, the Caliph. It's possible.
Know ye that at the right hand of the Indies there is an island called California close to that part of the Terrestrial Paradise, inhabited by black women without a single man among them, they lived in the manner of Amazons. They were robust of body with great virtue; the island itself is one of the wildest in the world on account of the craggy rocks. Shortened forms of the state's name include CA, Cal. Calif. and US-CA. Settled by successive waves of arrivals during the last 10,000 years, California was one of the most culturally and linguistically diverse areas in pre-Columbian North America. Various estimates of the native population range from 100,000 to 300,000; the Indigenous peoples of California included more than 70 distinct groups of Native Americans, ranging from large, settled populations living on the coast to groups in the interior. California groups were diverse in their political organization with bands, villages, on the resource-rich coasts, large chiefdoms, such as the Chumash and Salinan.
Trade, intermarriage a
Platycladus is a distinct genus of evergreen coniferous tree in the cypress family Cupressaceae, containing only one species, Platycladus orientalis known as Chinese thuja, Oriental arborvitae, Chinese arborvitae, biota or oriental thuja. It is native to northeastern parts of eastern Asia and north Asia, but is now naturalised as an introduced species elsewhere in Asia. Although accepted as the only member of its genus, it has been suggested that the related species Microbiota decussata could be included in Platycladus, but this is not followed. Other close relatives are Juniperus and Cupressus, both of these genera being graft-compatible with Platycladus. In older texts, Platycladus was included in Thuja, reflected in one of its common names, "oriental thuja", but it is only distantly related to the genus Thuja. Differences include its distinct cones, wingless seeds, its scentless foliage; the binomial Platycladus means "with broad or flattened shoots". The qualifier orientalis refers to its native habitat in China.
The common name'arborvitae' is from Latin,'tree of life', is based on its association with long life and vitality in Buddhist thought in China. This is based on the tree's unchanging evergreen nature in the cold dry climate of northwest China, its longevity, it is called cèbǎi in Chinese. A monoecious tree, it is small, slow-growing, reaching 15–20 m and 0.5 m trunk diameter. The foliage forms in flat sprays with scale-like leaves 2–4 mm long, which are bright green in colour but may turn brownish or coppery orange in winter; the cones are 1.5–2.5 cm long, green ripening brown in about eight months from pollination, have 6–12 thick scales arranged in opposite pairs. The seeds are 4–6 mm long, with no wing; the branches are short, loosely arranged and sharply directed upwards, the bark, brownish, is detached in narrow vertical strips. The twigs are arranged in vertical planes; the leaves, arranged in four rows, opposite, truncated, imbricated as adults, somewhat curved inwards, of uniform green color and with a resiniferous gland on the underside.
The female cones, of pink-salmon color and bluish-greenish when immature, centimetric and of annual maturation, are oval with 6-8 flattened, thick scales and provided with an apical hook. It is native to northwestern China, but it is delicate to distinguish the areas where they are native safely from those where they have been introduced, it is distributed in Manchuria, Russian Far East, now it is naturalised in Korea, Japan and Iran as well. It is cultivated in many parts of the world in parks, home yards and for hedges. Resistant to drought, it is often used as an ornamental tree, both in its homeland, where it is associated with long life and vitality, widely elsewhere in temperate climates, it is suitable for form cuts and year-round opaque hedges, but forms impressive slender solitary trees. Several cultivars have been selected, of which'Aurea Nana' has gained the Royal Horticultural Society's Award of Garden Merit; the wood is used in Buddhist temples both for construction work, chipped, for incense burning.
Its twigs and leaves contain 0.12% essential oil containing pinene and caryophyllene. The roots contain up to 2.75% of gasoline. Gymnosperm Database - Platycladus orientalis Arboretum de Villardebelle - Platycladus cone photos Conifers Around the World: Platycladus orientalis - Oriental Arborvitae
The term cultivar most refers to an assemblage of plants selected for desirable characters that are maintained during propagation. More cultivar refers to the most basic classification category of cultivated plants in the International Code of Nomenclature for Cultivated Plants. Most cultivars arose in cultivation. Popular ornamental garden plants like roses, daffodils and azaleas are cultivars produced by careful breeding and selection for floral colour and form; the world's agricultural food crops are exclusively cultivars that have been selected for characters such as improved yield and resistance to disease, few wild plants are now used as food sources. Trees used in forestry are special selections grown for their enhanced quality and yield of timber. Cultivars form a major part of Liberty Hyde Bailey's broader group, the cultigen, defined as a plant whose origin or selection is due to intentional human activity. A cultivar is not the same as a botanical variety, a taxonomic rank below subspecies, there are differences in the rules for creating and using the names of botanical varieties and cultivars.
In recent times, the naming of cultivars has been complicated by the use of statutory patents for plants and recognition of plant breeders' rights. The International Union for the Protection of New Varieties of Plants offers legal protection of plant cultivars to persons or organisations that introduce new cultivars to commerce. UPOV requires that a cultivar be "distinct, uniform", "stable". To be "distinct", it must have characters that distinguish it from any other known cultivar. To be "uniform" and "stable", the cultivar must retain these characters in repeated propagation; the naming of cultivars is an important aspect of cultivated plant taxonomy, the correct naming of a cultivar is prescribed by the Rules and Recommendations of the International Code of Nomenclature for Cultivated Plants. A cultivar is given a cultivar name, which consists of the scientific Latin botanical name followed by a cultivar epithet; the cultivar epithet is in a vernacular language. For example, the full cultivar name of the King Edward potato is Solanum tuberosum'King Edward'.'King Edward' is the cultivar epithet, according to the Rules of the Cultivated Plant Code, is bounded by single quotation marks.
The word cultivar originated from the need to distinguish between wild plants and those with characteristics that arose in cultivation, presently denominated cultigens. This distinction dates to the Greek philosopher Theophrastus, the "Father of Botany", keenly aware of this difference. Botanical historian Alan Morton noted that Theophrastus in his Historia Plantarum "had an inkling of the limits of culturally induced changes and of the importance of genetic constitution"; the International Code of Nomenclature for algae and plants uses as its starting point for modern botanical nomenclature the Latin names in Linnaeus' Species Plantarum and Genera Plantarum. In Species Plantarum, Linnaeus enumerated all plants known to him, either directly or from his extensive reading, he recognised the rank of varietas and he indicated these varieties with letters of the Greek alphabet, such as α, β, λ, before the varietal name, rather than using the abbreviation "var." as is the present convention. Most of the varieties that Linnaeus enumerated were of "garden" origin rather than being wild plants.
In time the need to distinguish between wild plants and those with variations, cultivated increased. In the nineteenth century many "garden-derived" plants were given horticultural names, sometimes in Latin and sometimes in a vernacular language. From circa the 1900s, cultivated plants in Europe were recognised in the Scandinavian and Slavic literature as stamm or sorte, but these words could not be used internationally because, by international agreement, any new denominations had to be in Latin. In the twentieth century an improved international nomenclature was proposed for cultivated plants. Liberty Hyde Bailey of Cornell University in New York, United States created the word cultivar in 1923 when he wrote that: The cultigen is a species, or its equivalent, that has appeared under domestication – the plant is cultigenous. I now propose another name, for a botanical variety, or for a race subordinate to species, that has originated under cultivation, it is the equivalent of the botanical variety except in respect to its origin.
In that essay, Bailey used only the rank of species for the cultigen, but it was obvious to him that many domesticated plants were more like botanical varieties than species, that realization appears to have motivated the suggestion of the new category of cultivar. Bailey created the word cultivar, assumed to be a portmanteau of cultivated and variety. Bailey never explicitly stated the etymology of cultivar, it has been suggested that it is instead a contraction of cultigen and variety, which seems correct; the neologism cultivar was promoted as "euphonious" and "free from ambiguity". The first Cultivated Plant Code of 1953 subsequently commended its use, by 1960 it had achieved common international acceptance; the words cultigen and cultivar may be confused with