Grex (horticulture)
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Grex (horticulture)
The term ''grex'' (plural ''greges'' or ''grexes''; abbreviation gx), derived from the Latin language, Latin noun , , meaning 'flock', has been expanded in botanical nomenclature to describe hybrids of orchids, based solely on their parentage. Grex names are one of the three categories of plant names governed by the International Code of Nomenclature for Cultivated Plants; within a grex the ''cultivar group'' category can be used to refer to plants by their shared characteristics (rather than by their parentage), and individual orchid plants can be selected (and propagated) and named as cultivars. Botanical nomenclature of hybrids The horticultural nomenclature of grexes exists within the framework of the botanical nomenclature of hybrid plants. Interspecific hybrids occur in nature, and are treated under the International Code of Nomenclature for algae, fungi, and plants as nothospecies, ('notho' indicating hybrid). They can optionally be given Linnean Binomial nomenclature, bin ...
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Grex (biology)
A grex, (also called a pseudoplasmodium, or slug) starts as a crowd of single-celled amoebae of the groups Acrasiomycota or Dictyosteliida; ''grex'' is the Latin word for ''flock''. The cells flock together, forming a mass that behaves as an organised, slug-like unit. Before they get stimulated to crowd together to form a grex, the amoebae simply wander as independent cells grazing on bacteria and other suitable food items. They continue in that way of life as long as conditions are favourable. When the amoebae are stressed, typically by a shortage of food, they form a grex. According to species and circumstances, details of the shape of the grex and how it may form will vary but typically the stressed amoebae first produce pheromones that stimulate the flock to vertically assemble in a column. When the column of aggregated cells becomes too high and narrow to stay upright, it topples and becomes a slug-shaped mass: the grex. The grex is mobile; in its form as a slug-like unit i ...
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Cattleya
''Cattleya'' () is a genus of orchids from Costa Rica south to Argentina. The genus is abbreviated C in trade journals. Description Epiphytic or terrestrial orchids with cylindrical rhizome from which the fleshy noodle-like roots grow. Pseudobulbs can be conical, spindle-shaped or cylindrical; with upright growth; one or two leaves growing from the top of them. The leaves can be oblong, lanceolate or elliptical, somewhat fleshy, with smooth margin. The inflorescence is a terminal raceme with few or several flowers. Flowers have sepals and petals free from each other; the lip or labellum (lowermost petal), usually has a different coloration and shape from the rest of the flower and covers in part the flower column forming a tube. There are four polliniums (bag-like organs that contain pollen). The fruit is a capsule with many small seeds.Schweinfurth, C., "Orchidaceae, Orchids of Peru", ''Fieldiana, Botany'' 30(3): 535 Taxonomy The genus was named in 1824 by John Lindley af ...
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Botanical Name
A botanical name is a formal scientific name conforming to the '' International Code of Nomenclature for algae, fungi, and plants'' (ICN) and, if it concerns a plant cultigen, the additional cultivar or Group epithets must conform to the ''International Code of Nomenclature for Cultivated Plants'' (ICNCP). The code of nomenclature covers "all organisms traditionally treated as algae, fungi, or plants, whether fossil or non-fossil, including blue-green algae ( Cyanobacteria), chytrids, oomycetes, slime moulds and photosynthetic protists with their taxonomically related non-photosynthetic groups (but excluding Microsporidia)." The purpose of a formal name is to have a single name that is accepted and used worldwide for a particular plant or plant group. For example, the botanical name ''Bellis perennis'' denotes a plant species which is native to most of the countries of Europe and the Middle East, where it has accumulated various names in many languages. Later, the plant was intro ...
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Epithet
An epithet (, ), also byname, is a descriptive term (word or phrase) known for accompanying or occurring in place of a name and having entered common usage. It has various shades of meaning when applied to seemingly real or fictitious people, divinities, objects, and binomial nomenclature. It can also be a descriptive title: for example, Pallas Athena, Phoebus Apollo, Alfred the Great, Suleiman the Magnificent, and Władysław I the Elbow-high. Many English monarchs have traditional epithets: some of the best known are Edward the Confessor, William the Conqueror, Richard the Lionheart, Æthelred the Unready, John Lackland and Bloody Mary. The word ''epithet'' can also refer to an abusive, defamatory, or derogatory phrase. This use as a euphemism is criticized by Martin Manser and other proponents of linguistic prescription. H. W. Fowler complained that "epithet is suffering a vulgarization that is giving it an abusive imputation." Linguistics Epithets are sometimes at ...
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Royal Horticultural Society
The Royal Horticultural Society (RHS), founded in 1804 as the Horticultural Society of London, is the UK's leading gardening charity. The RHS promotes horticulture through its five gardens at Wisley (Surrey), Hyde Hall (Essex), Harlow Carr (North Yorkshire), Rosemoor (Devon) and Bridgewater (Greater Manchester); flower shows including the Chelsea Flower Show, Hampton Court Palace Flower Show, Tatton Park Flower Show and Cardiff Flower Show; community gardening schemes; Britain in Bloom and a vast educational programme. It also supports training for professional and amateur gardeners. the president was Keith Weed and the director general was Sue Biggs CBE. History Founders The creation of a British horticultural society was suggested by John Wedgwood (son of Josiah Wedgwood) in 1800. His aims were fairly modest: he wanted to hold regular meetings, allowing the society's members the opportunity to present papers on their horticultural activities and discoveries, to enc ...
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Hybrid (biology)
In biology, a hybrid is the offspring resulting from combining the qualities of two organisms of different breeds, varieties, species or genera through sexual reproduction. Hybrids are not always intermediates between their parents (such as in blending inheritance), but can show hybrid vigor, 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 closely related the parent species are. Species are reproductively isolated by strong barriers to hybridisation, which include genetic and morphological differences, differing times of fertility, mating behaviors and cues, and 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 tim ...
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Species
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 often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. Other ways of defining species include their karyotype, DNA sequence, morphology, behaviour or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. The most recent rigorous estimate for the total number of species of eukaryotes is between 8 and 8.7 million. However, only about 14% of these had been described by 2011. All species (except viruses) are given a two-part name, a "binomial". The first part of a binomial is the genus to which the species belongs. The second part is called the specific name or the specific epithet (in botanical nomenclature, also sometimes i ...
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Sexual Reproduction
Sexual reproduction is a type of reproduction that involves a complex life cycle in which a gamete ( haploid reproductive cells, such as a sperm or egg cell) with a single set of chromosomes combines with another gamete to produce a zygote that develops into an organism composed of cells with two sets of chromosomes ( diploid). This is typical in animals, though the number of chromosome sets and how that number changes in sexual reproduction varies, especially among plants, fungi, and other eukaryotes. Sexual reproduction is the most common life cycle in multicellular eukaryotes, such as animals, fungi and plants. Sexual reproduction also occurs in some unicellular eukaryotes. Sexual reproduction does not occur in prokaryotes, unicellular organisms without cell nuclei, such bacteria and archaea. However, some process in bacteria may be considered analogous to sexual reproduction in that they incorporate new genetic information, including bacterial conjugation, transformatio ...
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Principle Of Priority
270px, '' valid name. Priority is a fundamental principle of modern botanical nomenclature and zoological nomenclature. Essentially, it is the principle of recognising the first valid application of a name to a plant or animal. There are two aspects to this: # The first formal scientific name given to a plant or animal taxon shall be the name that is to be used, called the valid name in zoology and correct name in botany (principle of synonymy). # Once a name has been used, no subsequent publication of that name for another taxon shall be valid (zoology) or validly published (botany) (principle of homonymy). Note that nomenclature for botany and zoology is independent, and the rules of priority regarding homonyms operate within each discipline but not between them. There are formal provisions for making exceptions to the principle of priority under each of the Codes. If an archaic or obscure prior name is discovered for an established taxon, the current name can be declared ...
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Synonym (taxonomy)
The Botanical and Zoological Codes of nomenclature treat the concept of synonymy differently. * In botanical nomenclature, a synonym is a scientific name that applies to a taxon that (now) goes by a different scientific name. For example, Linnaeus was the first to give a scientific name (under the currently used system of scientific nomenclature) to the Norway spruce, which he called ''Pinus abies''. This name is no longer in use, so it is now a synonym of the current scientific name, ''Picea abies''. * In zoology, moving a species from one genus to another results in a different binomen, but the name is considered an alternative combination rather than a synonym. The concept of synonymy in zoology is reserved for two names at the same rank that refers to a taxon at that rank - for example, the name ''Papilio prorsa'' Linnaeus, 1758 is a junior synonym of ''Papilio levana'' Linnaeus, 1758, being names for different seasonal forms of the species now referred to as ''Araschnia le ...
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Reciprocal Cross
In genetics, a reciprocal cross is a breeding experiment designed to test the role of parental sex on a given inheritance pattern. All parent organisms must be true breeding to properly carry out such an experiment. In one cross, a male expressing the trait of interest will be crossed with a female not expressing the trait. In the other, a female expressing the trait of interest will be crossed with a male not expressing the trait. It is the cross that could be made either way or independent of the sex of the parents. For example, suppose a biologist wished to identify whether a hypothetical allele Z, a variant of some gene A, is on the male or female sex chromosome. They might first cross a Z-trait female with an A-trait male and observe the offspring. Next, they would cross an A-trait female with a Z-trait male and observe the offspring. Via principles of dominant and recessive alleles, they could then (perhaps after cross-breeding the offspring as well) make an inference as to w ...
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Variety (botany)
In botanical nomenclature, variety (abbreviated var.; in la, varietas) is a taxonomic rank below that of species and subspecies, but above that of form. As such, it gets a three-part infraspecific name. It is sometimes recommended that the subspecies rank should be used to recognize geographic distinctiveness, whereas the variety rank is appropriate if the taxon is seen throughout the geographic range of the species. Example The pincushion cactus, ''Escobaria vivipara'' (Nutt.) Buxb., is a wide-ranging variable species occurring from Canada to Mexico, and found throughout New Mexico below about . Nine varieties have been described. Where the varieties of the pincushion cactus meet, they intergrade. The variety ''Escobaria vivipara'' var. ''arizonica'' is from Arizona, while ''Escobaria vivipara'' var. ''neo-mexicana'' is from New Mexico. See also '' Capsicum annuum var. glabriusculum'' Definitions The term is defined in different ways by different authors. However, the I ...
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