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
Royal Horticultural Society
The Royal Horticultural Society, founded in 1804 as the Horticultural Society of London, is the UK's leading gardening charity. The RHS promotes horticulture through flower shows including the Chelsea Flower Show, Hampton Court Palace Flower Show, Tatton Park Flower Show and Cardiff Flower Show, it supports training for professional and amateur gardeners. The current president is Sir Nicholas Bacon, 14th Baronet and the current director general is Sue Biggs CBE; the creation of a British horticultural society was suggested by John Wedgwood in 1800. His aims were modest: he wanted to hold regular meetings, allowing the society's members the opportunity to present papers on their horticultural activities and discoveries, to encourage discussion of them, to publish the results; the society would award prizes for gardening achievements. Wedgwood discussed the idea with his friends, but it was four years before the first meeting, of seven men, took place, on 7 March 1804 at Hatchards bookshop in Piccadilly, London.
Wedgwood was chairman. Banks proposed his friend Thomas Andrew Knight for membership; the proposal was accepted, despite Knight's ongoing feud with Forsyth over a plaster for healing tree wounds which Forsyth was developing. Knight was president of the society from 1811–1838, developed the society's aims and objectives to include a programme of practical research into fruit-breeding. In 2009, more than 363,000 people were members of the society, the number increased to more than 414,000 in 2013. Membership and fellowship of the society were decided by election, but are now by financial contribution. Fellowship may be secured through a "suggested" £5,000 donation each year. Members and Fellows of the Royal Horticultural Society are entitled to use the post-nominal letters MRHS and FRHS, respectively; the Royal Horticultural Society's four major gardens in England are: Wisley Garden, near Wisley in Surrey. The society's first garden was in Kensington, from 1818–1822. In 1820 the society leased some of Hugh Ronalds' nursery ground at Little Ealing to set up an experimental garden, but the next year part of the Duke of Devonshire's estate at Chiswick was obtained.
In 1823 it employed Joseph Paxton there. From 1827 the society held fêtes at the Chiswick garden, from 1833, shows with competitive classes for flowers and vegetables. In 1861 the RHS developed a new garden at South Kensington on land leased from the Royal Commission for the Exhibition of 1851, but it was closed in 1882; the Chiswick garden was maintained until 1903–1904, by which time Sir Thomas Hanbury had bought the garden at Wisley and presented it to the RHS. RHS Garden Wisley is thus the society's oldest garden. Rosemoor came next, presented by Lady Anne Berry in 1988. Hyde Hall was given to the RHS in 1993 by its owners Helen Robinson. Dick Robinson was the owner of the Harry Smith Collection, based at Hyde Hall; the most recent addition is Harlow Carr, acquired by the merger of the Northern Horticultural Society with the RHS in 2001. It had been the Northern Horticultural Society's trial ground and display garden since they bought it in 1949. In 2013, more than 1.63 million people visited the four gardens.
In 2015, the RHS announced plans for a fifth garden at Worsley New Hall, Greater Manchester, under the name RHS Garden Bridgewater. The RHS is well known for its annual flower shows which take place across the UK; the most famous of these shows is the RHS Chelsea Flower Show, visited by people from across world. This is followed by the Hampton Court Palace Flower Show and RHS Tatton Park Flower Show in Cheshire; the most recent addition to the RHS shows line-up is the RHS Show Cardiff, held at Cardiff Castle since 2005. The society is closely involved with the spring and autumn shows at Malvern and with BBC Gardeners' World Live held annually at the Birmingham National Exhibition Centre; the RHS is custodian of the Lindley Library, housed within its headquarters at 80 Vincent Square, in branches at each of its four gardens. The library is based upon the book collection of John Lindley; the RHS Herbarium has its own image library consisting of more than 3,300 original watercolours 30,000 colour slides and a increasing number of digital images.
Although most of the images have been supplied by photographers commissioned by the RHS, the archive includes a substantial number of slides from the Harry Smith Collection and Plant Heritage National Plant Collection holders. The reference library at Wisley Garden is open to visitors to the Garden. In 2002, the RHS took over the administration of the Britain in Bloom competition from the Tidy Britain Group. In 2010, The society launched'It's your neighbourhood', a campaign to encourage people to get involved in horticulture for the benefit of their community. In 2014, the'Britain in Bloom' celebrates its 50th anniversary; the RHS runs formal courses for professional and amateur gardeners and horticulturalists and validates qualifications gained elsewhere. The RHS Level 1 Award in
Erysimum is a genus of flowering plants in the cabbage family. It includes about 180 species of many wild forms; the genus Cheiranthus is sometimes included here in part. Erysimum has since the early 21st century been ascribed to a monogeneric cruciferous tribe, characterised by sessile, stellate and/or malpighiaceous trichomes, yellow to orange flowers and multiseeded siliques. Wallflowers are herbaceous perennials or sub-shrubs; the perennial species are short-lived and in cultivation treated as biennials. Most species have stems erect, somewhat winged, canescent with an indumentum of bifid hairs 25 ± 53 cm × 2–3 mm in size, t-shaped trichomes; the leaves are sessile. The lower leaves are linear to oblanceolate pinnatifid with backwardly directed lobes, acute, 50–80 mm × 0.5–3 mm. Stem leaves are linear, all canescent with 2-fid hairs. Flowering occurs during summer. One species, Erysimum semperflorens, native to Morocco and Algeria, has white flowers; the floral pedicel ranges from 4 to 7 mm. Four free sepals somewhat saccate, light green, 5–7 mm × 1.5–2 mm.
The genus name Erysimum is derived from the Greek word'Eryo' meaning to drag. Wallflowers are native to southwest Asia, the Mediterranean, Africa and North America through Costa Rica. Many wallflowers are endemic to small areas, such as: E. aetnense E. franciscanum Erysimum kykkoticum E. moranii E. nevadense E. scoparium E. teretifolium Most wallflower garden cultivars are derived from E. cheiri, from southern Europe. They are attacked by fungal and bacterial disease, so they are best grown as biennials and discarded after flowering, they are susceptible to clubroot, a disease of Brassicaceae. Growth is best in dry soils with good drainage, they are grown in loose wall mortar, hence the vernacular name. There is a wide range of flower color in the warm spectrum, including white, orange, pink, maroon and brown; the flowers, appearing in spring have a strong fragrance. Wallflowers are associated in spring bedding schemes with tulips and forget-me-nots; the cultivar'Bowles's Mauve' has gained the Royal Horticultural Society's Award of Garden Merit.
Erysimum species are used as food plants by the larvae of some Lepidoptera species including the Garden Carpet. In addition, some species of weevils, like Ceutorhynchus chlorophanus, live inside the fruits feeding on the developing seeds. Many species of beetles and grasshoppers eat the leaves and stalks; some mammalian herbivores, for example Mule Deer in North America, Argali in Mongolia, Red Deer in Central Europe, or Spanish Ibex in the Iberian Peninsula, feed on wallflower flowering and fruiting stalks. Most wallflowers are pollinator-generalists, their flowers being visited by many different species of bees, bee flies, butterflies and ants. However, there are some specialist species. For example, Erysimum scoparium is pollinated exclusively by Anthophora alluadii. Evoflor, a web page on Erysimum floral evolution webpage of a UK collector of erysimums Herbario del Instituto Pirenaico de Ecología, CSIC Botánica Sistemática, an open web on plants
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 flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants. The biological function of a flower is to effect reproduction by providing a mechanism for the union of sperm with eggs. Flowers may allow selfing; some flowers produce diaspores without fertilization. Flowers are the site where gametophytes develop. Many flowers have evolved to be attractive to animals, so as to cause them to be vectors for the transfer of pollen. After fertilization, the ovary of the flower develops into fruit containing seeds. In addition to facilitating the reproduction of flowering plants, flowers have long been admired and used by humans to bring beauty to their environment, as objects of romance, religion, medicine and as a source of food; the essential parts of a flower can be considered in two parts: the vegetative part, consisting of petals and associated structures in the perianth, the reproductive or sexual parts. A stereotypical flower consists of four kinds of structures attached to the tip of a short stalk.
Each of these kinds of parts is arranged in a whorl on the receptacle. The four main whorls are as follows: Collectively the calyx and corolla form the perianth. Calyx: the outermost whorl consisting of units called sepals. Corolla: the next whorl toward the apex, composed of units called petals, which are thin and colored to attract animals that help the process of pollination. Androecium: the next whorl, consisting of units called stamens. Stamens consist of two parts: a stalk called a filament, topped by an anther where pollen is produced by meiosis and dispersed. Gynoecium: the innermost whorl of a flower, consisting of one or more units called carpels; the carpel or multiple fused carpels form a hollow structure called an ovary, which produces ovules internally. Ovules are megasporangia and they in turn produce megaspores by meiosis which develop into female gametophytes; these give rise to egg cells. The gynoecium of a flower is described using an alternative terminology wherein the structure one sees in the innermost whorl is called a pistil.
A pistil may consist of a number of carpels fused together. The sticky tip of the pistil, the stigma, is the receptor of pollen; the supportive stalk, the style, becomes the pathway for pollen tubes to grow from pollen grains adhering to the stigma. The relationship to the gynoecium on the receptacle is described as hypogynous, perigynous, or epigynous. Although the arrangement described above is considered "typical", plant species show a wide variation in floral structure; these modifications have significance in the evolution of flowering plants and are used extensively by botanists to establish relationships among plant species. The four main parts of a flower are defined by their positions on the receptacle and not by their function. Many flowers lack some parts or parts may be modified into other functions and/or look like what is another part. In some families, like Ranunculaceae, the petals are reduced and in many species the sepals are colorful and petal-like. Other flowers have modified stamens.
Flowers show great variation and plant scientists describe this variation in a systematic way to identify and distinguish species. Specific terminology is used to describe their parts. Many flower parts are fused together; when petals are fused into a tube or ring that falls away as a single unit, they are sympetalous. Connate petals may have distinctive regions: the cylindrical base is the tube, the expanding region is the throat and the flaring outer region is the limb. A sympetalous flower, with bilateral symmetry with an upper and lower lip, is bilabiate. Flowers with connate petals or sepals may have various shaped corolla or calyx, including campanulate, tubular, salverform or rotate. Referring to "fusion," as it is done, appears questionable because at least some of the processes involved may be non-fusion processes. For example, the addition of intercalary growth at or below the base of the primordia of floral appendages such as sepals, petals and carpels may lead to a common base, not the result of fusion.
Many flowers have a symmetry. When the perianth is bisected through the central axis from any point and symmetrical halves are produced, the flower is said to be actinomorphic or regular, e.g. rose or trillium. This is an example of radial symmetry; when flowers are bisected and produce only one line that produces symmetrical halves, the flower is said to be irregular or zygomorphic, e.g. snapdragon or most orchids. Flowers may be directly attached to the plant at their base; the stem or stalk subtending a flower is called a peduncle. If a peduncle supports more than o
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring by sexual reproduction. Other ways of defining species include their karyotype, DNA sequence, behaviour or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. While these definitions may seem adequate, when looked at more they represent problematic species concepts. For example, the boundaries between related species become unclear with hybridisation, in a species complex of hundreds of similar microspecies, in a ring species. Among organisms that reproduce only asexually, the concept of a reproductive species breaks down, each clone is a microspecies. All species are given a two-part name, a "binomial"; the first part of a binomial is the genus.
The second part is called the specific epithet. For example, Boa constrictor is one of four species of the genus Boa. None of these is satisfactory definitions, but scientists and conservationists need a species definition which allows them to work, regardless of the theoretical difficulties. If species were fixed and distinct from one another, there would be no problem, but evolutionary processes cause species to change continually, to grade into one another. Species were seen from the time of Aristotle until the 18th century as fixed kinds that could be arranged in a hierarchy, the great chain of being. In the 19th century, biologists grasped. Charles Darwin's 1859 book The Origin of Species explained how species could arise by natural selection; that understanding was extended in the 20th century through genetics and population ecology. Genetic variability arises from mutations and recombination, while organisms themselves are mobile, leading to geographical isolation and genetic drift with varying selection pressures.
Genes can sometimes be exchanged between species by horizontal gene transfer. Viruses are a special case, driven by a balance of mutation and selection, can be treated as quasispecies. Biologists and taxonomists have made many attempts to define species, beginning from morphology and moving towards genetics. Early taxonomists such as Linnaeus had no option but to describe what they saw: this was formalised as the typological or morphological species concept. Ernst Mayr emphasised reproductive isolation, but this, like other species concepts, is hard or impossible to test. Biologists have tried to refine Mayr's definition with the recognition and cohesion concepts, among others. Many of the concepts are quite similar or overlap, so they are not easy to count: the biologist R. L. Mayden recorded about 24 concepts, the philosopher of science John Wilkins counted 26. Wilkins further grouped the species concepts into seven basic kinds of concepts: agamospecies for asexual organisms biospecies for reproductively isolated sexual organisms ecospecies based on ecological niches evolutionary species based on lineage genetic species based on gene pool morphospecies based on form or phenotype and taxonomic species, a species as determined by a taxonomist.
A typological species is a group of organisms in which individuals conform to certain fixed properties, so that pre-literate people recognise the same taxon as do modern taxonomists. The clusters of variations or phenotypes within specimens would differentiate the species; this method was used as a "classical" method of determining species, such as with Linnaeus early in evolutionary theory. However, different phenotypes are not different species. Species named in this manner are called morphospecies. In the 1970s, Robert R. Sokal, Theodore J. Crovello and Peter Sneath proposed a variation on this, a phenetic species, defined as a set of organisms with a similar phenotype to each other, but a different phenotype from other sets of organisms, it differs from the morphological species concept in including a numerical measure of distance or similarity to cluster entities based on multivariate comparisons of a reasonably large number of phenotypic traits. A mate-recognition species is a group of sexually reproducing organisms that recognize one another as potential mates.
Expanding on this to allow for post-mating isolation, a cohesion species is the most inclusive population of individuals having the potential for phenotypic cohesion through intrinsic cohesion mechanisms. A further development of the recognition concept is provided by the biosemiotic concept of species. In microbiology, genes can move even between distantly related bacteria extending to the whole bacterial domain; as a rule of thumb, microbiologists have assumed that kinds of Bacteria or Archaea with 16S ribosomal RNA gene sequences more similar than 97% to each other need to be checked by DNA-DNA hybridisation to decide if they belong to the same species or not. This concept was narrowed in 2006 to a similarity of 98.7%. DNA-DNA hybri
Erysimum cheiri syn. Cheiranthus cheiri is a species of flowering plant in the family Brassicaceae, native to Europe but widespread as an introduced species elsewhere, it is widely cultivated as a garden plant. It is known as giroflée and ravenelle in French, Goldlack in German, alhelí in Spanish and violacciocca in Italian; the common name "wallflower" attaches to all cultivars of this plant, as well as other species within the genus Erysimum and the former genus Cheiranthus. This is a herbaceous perennial grown as a biennial, with one or more branching stems reaching heights of 15–80 cm; the leaves are narrow and pointed and may be up to 20 cm long. The top of the stem is occupied by a club-shaped inflorescence of scented flowers; each flower has purplish-green sepals and rounded petals which are two to three centimeters long and in shades of bright yellows to reds and purples. The flowers fall away to leave long fruits which are narrow, hairy siliques several centimeters in length; this is a popular ornamental plant cultivated for its abundant, fragrant flowers in spring.
Many cultivars have been developed, in shades of yellow, red, purple, brown and cream. It associates well in bedding schemes with other spring flowers such as forget-me-nots, it is grown as a biennial, sown one year to flower the next, discarded. This is because of its tendency to grow spindly and leggy during its second year, but more its susceptibility to infections such as clubroot. A miniature yellow double leafed wallflower was rediscovered by Rev. Henry Harpur-Crewe and is now named ‘Harpur Crewe’. Other bred varieties may vary quite a bit in appearance from the wild plant; the following cultivars have gained the Royal Horticultural Society’s Award of Garden Merit:- ’Sunset Apricot’ ’Sunset Primrose’ Other varieties such as'Blood Red Covent Garden' are easy to grow and benefit from being sown and left to their own devices, growing on patches of empty land with little effort required to maintain them, providing aesthetically sound blooms which produce strong scents. Jepson Manual Treatment USDA Plants Profile Photo gallery