In biology, poisons are substances that cause disturbances in organisms by chemical reaction or other activity on the molecular scale, when an organism absorbs a sufficient quantity. The fields of medicine and zoology distinguish a poison from a toxin, from a venom. Toxins are poisons produced by organisms in nature, venoms are toxins injected by a bite or sting; the difference between venom and other poisons is the delivery method. Industry and other sectors employ poisonous substances for reasons other than their toxicity. Most poisonous industrial compounds have associated material safety data sheets and are classed as hazardous substances. Hazardous substances are subject to extensive regulation on production and use in overlapping domains of occupational safety and health, public health, drinking water quality standards, air pollution and environmental protection. Due to the mechanics of molecular diffusion, many poisonous compounds diffuse into biological tissues, water, or soil on a molecular scale.
By the principle of entropy, chemical contamination is costly or infeasible to reverse, unless specific chelating agents or micro-filtration processes are available. Chelating agents are broader in scope than the acute target, therefore their ingestion necessitates careful medical or veterinarian supervision. Pesticides are one group of substances whose toxicity to various insects and other animals deemed to be pests is their prime purpose. Natural pesticides have been used for this purpose for thousands of years. Bioaccumulation of chemically-prepared agricultural insecticides is a matter of concern for the many species birds, which consume insects as a primary food source. Selective toxicity, controlled application, controlled biodegradation are major challenges in herbicide and pesticide development and in chemical engineering as all lifeforms on earth share an underlying biochemistry. A poison which enters the food chain—whether of industrial, agricultural, or natural origin—might not be toxic to the first organism that ingests the toxin, but can become further concentrated in predatory organisms further up the food chain carnivores and omnivores concerning fat soluble poisons which tend to become stored in biological tissue rather than excreted in urine or other water-based effluents.
Two common cases of acute natural poisoning are theobromine poisoning of dogs and cats, mushroom poisoning in humans. Dogs and cats are not natural herbivores, but a chemical defense developed by Theobroma cacao can be incidentally fatal nevertheless. Many omnivores, including humans consume edible fungi, thus many fungi have evolved to become decisively inedible, in this case as a direct defense. Apart from food, many poisons enter the body through the skin and lungs. Hydrofluoric acid is a notorious contact poison, in addition to its corrosive damage. Occurring sour gas is a notorious, fast-acting atmospheric poison. Plant-based contact irritants, such as that possessed by poison ivy or poison oak, are classed as allergens rather than poisons. Poison can enter the body through the teeth, faulty medical implants, or by injection. In 2013, 3.3 million cases of unintentional human poisonings occurred. This resulted in 98,000 deaths worldwide, down from 120,000 deaths in 1990. In modern society, cases of suspicious death elicit the attention of the Coroner's office and forensic investigators.
While arsenic is a occurring environmental poison, its artificial concentrate was once nicknamed inheritance powder. In Medieval Europe, it was common for monarchs to employ personal food tasters to thwart royal assassination, in the dawning age of the Apothecary. Of increasing concern since the isolation of natural radium by Marie and Pierre Curie in 1898—and the subsequent advent of nuclear physics and nuclear technologies—are radiological poisons; these are associated with ionizing radiation, a mode of toxicity quite distinct from chemically active poisons. In mammals, chemical poisons are passed from mother to offspring through the placenta during gestation, or through breast milk during nursing. In contrast, radiological damage can be passed from mother or father to offspring through genetic mutation, which—if not fatal in miscarriage or childhood, or a direct cause of infertility—can be passed along again to a subsequent generation. Atmospheric radon is a natural radiological poison of increasing impact since humans moved from hunter-gatherer lifestyles though cave dwelling to enclosed structures able to contain radon in dangerous concentrations.
The 2006 poisoning of Alexander Litvinenko was a novel use of radiological assassination meant to evade the normal investigation of chemical poisons. Poisons dispersed into the environment are known as pollution; these are of human origin, but pollution can include unwanted biological processes such as toxic red tide, or acute changes to the natural chemical environment attributed to invasive species, which are toxic or detrimental to the prior ecology (especially if the prior ecology was associated with human economic valu
Ornamental plants are plants that are grown for decorative purposes in gardens and landscape design projects, as houseplants, cut flowers and specimen display. The cultivation of ornamental plants is called floriculture, which forms a major branch of horticulture. Ornamental plants are grown for the display of aesthetic features including: flowers, scent, overall foliage texture, fruit and bark, aesthetic form. In some cases, unusual features may be considered to be of interest, such as the prominent thorns of Rosa sericea and cacti. In all cases, their purpose is for the enjoyment of gardeners and the public institutions. Certain trees may be called ornamental trees; this term is used when they are used as part of a garden, park, or landscape setting, for instance for their flowers, their texture, form and shape, other aesthetic characteristics. In some countries trees in'utilitarian' landscape use such as screening, roadside plantings are called amenity trees. Ornamental grasses are grasses grown as ornamental plants.
Many ornamental grasses are true grasses, however several other families of grass-like plants are marketed as ornamental grasses. These include the sedges, rushes and cat-tails. All are monocotyledons with narrow leaves and parallel veins. Most are herbaceous perennials, though many are evergreen and some develop woody tissues. Ornamental grasses are popular in many countries, they bring striking linear form, color and sound to the garden, throughout the year. Ornamental grasses are popular in many colder hardiness zones for their resilience to cold temperatures and aesthetic value throughout fall and winter seasons. For plants to be considered ornamental, they require specific pruning by a gardener. For instance, many plants cultivated for topiary and bonsai would only be considered to be ornamental by virtue of the regular pruning carried out on them by the gardener, they may cease to be ornamental if the work was abandoned. Ornamental plants and trees are distinguished from utilitarian and crop plants, such as those used for agriculture and vegetable crops, for forestry or as fruit trees.
This does not preclude any particular type of plant being grown both for ornamental qualities in the garden, for utilitarian purposes in other settings. Thus lavender is grown as an ornamental plant in gardens, but may be grown as a crop plant for the production of lavender oil; the term ornamental plant is used here in the same sense that it is used in the horticultural trades. The term corresponds to'garden plant', though the latter is much less precise, as any plant may be grown in a garden. Ornamental plants are plants, rather than functional ones. While some plants are both ornamental and functional, people use the term “ornamental plants” to refer to plants which have no value beyond being attractive, although many people feel that this is value enough. Ornamental plants are the keystone of ornamental gardening, they come in a range of shapes and colors suitable to a broad array of climates and gardening needs; some ornamental plants are grown for showy foliage. Their foliage may be deciduous, turning bright orange and yellow before dropping off in the fall, or evergreen, in which case it stays green year-round.
Some ornamental foliage has a striking appearance created by lacy leaves or long needles, while other ornamentals are grown for distinctively colored leaves, such as silvery-gray ground covers and bright red grasses, among many others. Other ornamental plants are cultivated for their blooms. Flowering ornamentals are a key aspect of many gardens, with many flower gardeners preferring to plant a variety of flowers so that the garden is continuously in flower through the spring and summer. Depending on the types of plants being grown, the flowers may be subtle and delicate, or large and showy, with some ornamental plants producing distinctive aromas which paint a palette of scents in addition to colors. Media related to Ornamental plants at Wikimedia Commons
A seed is an embryonic plant enclosed in a protective outer covering. The formation of the seed is part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiosperm plants. Seeds are the product of the ripened ovule, after fertilization by pollen and some growth within the mother plant; the embryo is developed from the seed coat from the integuments of the ovule. Seeds have been an important development in the reproduction and success of gymnosperm and angiosperm plants, relative to more primitive plants such as ferns and liverworts, which do not have seeds and use water-dependent means to propagate themselves. Seed plants now dominate biological niches on land, from forests to grasslands both in hot and cold climates; the term "seed" has a general meaning that antedates the above – anything that can be sown, e.g. "seed" potatoes, "seeds" of corn or sunflower "seeds". In the case of sunflower and corn "seeds", what is sown is the seed enclosed in a shell or husk, whereas the potato is a tuber.
Many structures referred to as "seeds" are dry fruits. Plants producing berries are called baccate. Sunflower seeds are sometimes sold commercially while still enclosed within the hard wall of the fruit, which must be split open to reach the seed. Different groups of plants have other modifications, the so-called stone fruits have a hardened fruit layer fused to and surrounding the actual seed. Nuts are the one-seeded, hard-shelled fruit of some plants with an indehiscent seed, such as an acorn or hazelnut. Seeds are produced in several related groups of plants, their manner of production distinguishes the angiosperms from the gymnosperms. Angiosperm seeds are produced in a hard or fleshy structure called a fruit that encloses the seeds for protection in order to secure healthy growth; some fruits have layers of both fleshy material. In gymnosperms, no special structure develops to enclose the seeds, which begin their development "naked" on the bracts of cones. However, the seeds do become covered by the cone scales.
Seed production in natural plant populations varies from year to year in response to weather variables and diseases, internal cycles within the plants themselves. Over a 20-year period, for example, forests composed of loblolly pine and shortleaf pine produced from 0 to nearly 5 million sound pine seeds per hectare. Over this period, there were six bumper, five poor, nine good seed crops, when evaluated for production of adequate seedlings for natural forest reproduction. Angiosperm seeds consist of three genetically distinct constituents: the embryo formed from the zygote, the endosperm, triploid, the seed coat from tissue derived from the maternal tissue of the ovule. In angiosperms, the process of seed development begins with double fertilization, which involves the fusion of two male gametes with the egg cell and the central cell to form the primary endosperm and the zygote. Right after fertilization, the zygote is inactive, but the primary endosperm divides to form the endosperm tissue.
This tissue becomes the food the young plant will consume until the roots have developed after germination. After fertilization the ovules develop into the seeds; the ovule consists of a number of components: The funicle or seed stalk which attaches the ovule to the placenta and hence ovary or fruit wall, at the pericarp. The nucellus, the remnant of the megasporangium and main region of the ovule where the megagametophyte develops; the micropyle, a small pore or opening in the apex of the integument of the ovule where the pollen tube enters during the process of fertilization. The chalaza, the base of the ovule opposite the micropyle, where integument and nucellus are joined together; the shape of the ovules as they develop affects the final shape of the seeds. Plants produce ovules of four shapes: the most common shape is called anatropous, with a curved shape. Orthotropous ovules are straight with all the parts of the ovule lined up in a long row producing an uncurved seed. Campylotropous ovules have a curved megagametophyte giving the seed a tight "C" shape.
The last ovule shape is called amphitropous, where the ovule is inverted and turned back 90 degrees on its stalk. In the majority of flowering plants, the zygote's first division is transversely oriented in regards to the long axis, this establishes the polarity of the embryo; the upper or chalazal pole becomes the main area of growth of the embryo, while the lower or micropylar pole produces the stalk-like suspensor that attaches to the micropyle. The suspensor absorbs and manufactures nutrients from the endosperm that are used during the embryo's growth; the main components of the embryo are: The cotyledons, the seed leaves, attached to the embryonic axis. There may be two; the cotyledons are the source of nutrients in the non-endospermic dicotyledons, in which case they replace the endosperm, are thick and leathery. In endospermic seeds the cotyledons are papery. Dicotyledons have the point of attachment opposite one another on the axis; the epicotyl, the embryonic axis above the point of attachment of the cotyledon.
The plumule, the tip of the epicotyl, has a feathery appearance due to the presence of young leaf primordia at the apex, will become the shoot upon germination. The hypocotyl, the embryonic axis below the point of attachment of the cotyledon, connecting the epicotyl and the radicle, being the stem-root transition zone; the radicle, the basal tip of the hy
A cone is an organ on plants in the division Pinophyta that contains the reproductive structures. The familiar woody cone is the female cone; the male cones, which produce pollen, are herbaceous and much less conspicuous at full maturity. The name "cone" derives from the fact; the individual plates of a cone are known as scales. The male cone is structurally similar across all conifers, differing only in small ways from species to species. Extending out from a central axis are microsporophylls. Under each microsporophyll is several microsporangia; the female cone contains ovules. The female cone structure varies more markedly between the different conifer families, is crucial for the identification of many species of conifers; the members of the pine family have cones. These pine cones the woody female cones, are considered the "archetypal" tree cones; the female cone has two types of scale: the bract scales, the seed scales, one subtended by each bract scale, derived from a modified branchlet. On the upper-side base of each seed scale are two ovules that develop into seeds after fertilization by pollen grains.
The bract scales develop first, are conspicuous at the time of pollination. The scales open temporarily to receive gametophytes close during fertilization and maturation, re-open again at maturity to allow the seed to escape. Maturation takes 6–8 months from pollination in most Pinaceae genera, but 12 months in cedars and 18–24 months in most pines; the cones open either by the seed scales flexing back when they dry out, or by the cones disintegrating with the seed scales falling off. The cones are conic, cylindrical or ovoid, small to large, from 2–60 cm long and 1–20 cm broad. After ripening, the opening of non-serotinous pine cones is associated with their moisture content—cones are open when dry and closed when wet; this assures that the small, wind disseminated seeds will be dispersed during dry weather, thus, the distance traveled from the parent tree will be enhanced. A pine cone will go through many cycles of opening and closing during its life span after seed dispersal is complete; this process occurs with older cones while attached to branches and after the older cones have fallen to the forest floor.
The condition of fallen pine cones is a crude indication of the forest floor's moisture content, an important indication of wildfire risk. Closed cones indicate damp conditions; as a result of this, pine cones have been used by people in temperate climates to predict dry and wet weather hanging a harvested pine cone from some string outside to measure the humidity of the air. Members of the Araucariaceae have the bract and seed scales fused, have only one ovule on each scale; the cones are spherical or nearly so, large to large, 5–30 cm diameter, mature in 18 months. In Agathis, the seeds are winged and separate from the seed scale, but in the other two genera, the seed is wingless and fused to the scale; the cones of the Podocarpaceae are similar in function, though not in development, to those of the Taxaceae, being berry-like with the scales modified, evolved to attract birds into dispersing the seeds. In most of the genera, two to ten or more scales are fused together into a swollen, brightly coloured, edible fleshy aril.
Only one or two scales at the apex of the cone are fertile, each bearing a single wingless seed, but in Saxegothaea several scales may be fertile. The fleshy scale complex is 0.5–3 cm long, the seeds 4–10 mm long. In some genera, the scales are minute and not fleshy, but the seed coat develops a fleshy layer instead, the cone having the appearance of one to three small plums on a central stem; the seeds have a hard coat evolved to resist digestion in the bird's stomach. Members of the cypress family differ in that the bract and seed scales are fused, with the bract visible as no more than a small lump or spine on the scale; the botanical term galbulus is sometimes used instead of strobilus for members of this family. The female cones have one to 20 ovules on each scale, they have peltate scales, as opposed to the imbricate cones described above, though some have imbricate scales. The cones are small, 0.3–6 cm or 1⁄8–2 3⁄8 inches long, spherical or nearly so, like those of Nootka cypress, while others, such as western redcedar and California incense-cedar, are narrow.
The scales are arranged either spirally, or in decussate whorls of two or three four. The genera with spiral scale arrangement were treated in a separate family in the past. In most of the genera, the cones are woody and the seeds have two narrow wings, but in three genera, the seeds are wingless, in Juniperus, the cones are fleshy and
A mountain is a large landform that rises above the surrounding land in a limited area in the form of a peak. A mountain is steeper than a hill. Mountains are formed through tectonic forces or volcanism; these forces can locally raise the surface of the earth. Mountains erode through the action of rivers, weather conditions, glaciers. A few mountains are isolated summits. High elevations on mountains produce colder climates than at sea level; these colder climates affect the ecosystems of mountains: different elevations have different plants and animals. Because of the less hospitable terrain and climate, mountains tend to be used less for agriculture and more for resource extraction and recreation, such as mountain climbing; the highest mountain on Earth is Mount Everest in the Himalayas of Asia, whose summit is 8,850 m above mean sea level. The highest known mountain on any planet in the Solar System is Olympus Mons on Mars at 21,171 m. There is no universally accepted definition of a mountain.
Elevation, relief, steepness and continuity have been used as criteria for defining a mountain. In the Oxford English Dictionary a mountain is defined as "a natural elevation of the earth surface rising more or less abruptly from the surrounding level and attaining an altitude which to the adjacent elevation, is impressive or notable."Whether a landform is called a mountain may depend on local usage. Mount Scott outside Lawton, Oklahoma, USA, is only 251 m from its base to its highest point. Whittow's Dictionary of Physical Geography states "Some authorities regard eminences above 600 metres as mountains, those below being referred to as hills." In the United Kingdom and the Republic of Ireland, a mountain is defined as any summit at least 2,000 feet high, whilst the official UK government's definition of a mountain, for the purposes of access, is a summit of 600 metres or higher. In addition, some definitions include a topographical prominence requirement 100 or 500 feet. At one time the U.
S. Board on Geographic Names defined a mountain as being 1,000 feet or taller, but has abandoned the definition since the 1970s. Any similar landform lower. However, the United States Geological Survey concludes that these terms do not have technical definitions in the US; the UN Environmental Programme's definition of "mountainous environment" includes any of the following: Elevation of at least 2,500 m. Using these definitions, mountains cover 33% of Eurasia, 19% of South America, 24% of North America, 14% of Africa; as a whole, 24% of the Earth's land mass is mountainous. There are three main types of mountains: volcanic and block. All three types are formed from plate tectonics: when portions of the Earth's crust move and dive. Compressional forces, isostatic uplift and intrusion of igneous matter forces surface rock upward, creating a landform higher than the surrounding features; the height of the feature makes it either a hill or, if steeper, a mountain. Major mountains tend to occur in long linear arcs, indicating tectonic plate boundaries and activity.
Volcanoes are formed when a plate is pushed at a mid-ocean ridge or hotspot. At a depth of around 100 km, melting occurs in rock above the slab, forms magma that reaches the surface; when the magma reaches the surface, it builds a volcanic mountain, such as a shield volcano or a stratovolcano. Examples of volcanoes include Mount Pinatubo in the Philippines; the magma does not have to reach the surface in order to create a mountain: magma that solidifies below ground can still form dome mountains, such as Navajo Mountain in the US. Fold mountains occur when two plates collide: shortening occurs along thrust faults and the crust is overthickened. Since the less dense continental crust "floats" on the denser mantle rocks beneath, the weight of any crustal material forced upward to form hills, plateaus or mountains must be balanced by the buoyancy force of a much greater volume forced downward into the mantle, thus the continental crust is much thicker under mountains, compared to lower lying areas.
Rock can fold either asymmetrically. The upfolds are anticlines and the downfolds are synclines: in asymmetric folding there may be recumbent and overturned folds; the Balkan Mountains and the Jura Mountains are examples of fold mountains. Block mountains are caused by faults in the crust: a plane; when rocks on one side of a fault rise relative to the other, it can form a mountain. The uplifted blocks are block horsts; the intervening dropped blocks are termed graben: these can be small or form extensive rift valley systems. This form of landscape can be seen in East Africa, the Vosges, the Basin and Range Province of Western North America and the Rhine valley; these areas occur when the regional stress is extensional and the crust is thinned. During and following uplift, mountains are subjected to the agents of erosion which wear the uplifted area down. Erosion causes the surface of mountains to be younger than the rocks that form the mountains themselves. Glacial processes produce characteristic landforms, such as pyramidal peaks, knife-edge arêtes, bowl-shaped cirques that can contai
Binomial nomenclature called binominal nomenclature or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin grammatical forms, although they can be based on words from other languages. Such a name is called a binomen, binominal name or a scientific name; the first part of the name – the generic name – identifies the genus to which the species belongs, while the second part – the specific name or specific epithet – identifies the species within the genus. For example, humans belong within this genus to the species Homo sapiens. Tyrannosaurus rex is the most known binomial; the formal introduction of this system of naming species is credited to Carl Linnaeus beginning with his work Species Plantarum in 1753. But Gaspard Bauhin, in as early as 1623, had introduced in his book Pinax theatri botanici many names of genera that were adopted by Linnaeus; the application of binomial nomenclature is now governed by various internationally agreed codes of rules, of which the two most important are the International Code of Zoological Nomenclature for animals and the International Code of Nomenclature for algae and plants.
Although the general principles underlying binomial nomenclature are common to these two codes, there are some differences, both in the terminology they use and in their precise rules. In modern usage, the first letter of the first part of the name, the genus, is always capitalized in writing, while that of the second part is not when derived from a proper noun such as the name of a person or place. Both parts are italicized when a binomial name occurs in normal text, thus the binomial name of the annual phlox is now written as Phlox drummondii. In scientific works, the authority for a binomial name is given, at least when it is first mentioned, the date of publication may be specified. In zoology "Patella vulgata Linnaeus, 1758"; the name "Linnaeus" tells the reader who it was that first published a description and name for this species of limpet. "Passer domesticus". The original name given by Linnaeus was Fringilla domestica; the ICZN does not require that the name of the person who changed the genus be given, nor the date on which the change was made, although nomenclatorial catalogs include such information.
In botany "Amaranthus retroflexus L." – "L." is the standard abbreviation used in botany for "Linnaeus". "Hyacinthoides italica Rothm. – Linnaeus first named this bluebell species Scilla italica. The name is composed of two word-forming elements: "bi", a Latin prefix for two, "-nomial", relating to a term or terms; the word "binomium" was used in Medieval Latin to mean a two-term expression in mathematics. Prior to the adoption of the modern binomial system of naming species, a scientific name consisted of a generic name combined with a specific name, from one to several words long. Together they formed a system of polynomial nomenclature; these names had two separate functions. First, to designate or label the species, second, to be a diagnosis or description. In a simple genus, containing only two species, it was easy to tell them apart with a one-word genus and a one-word specific name; such "polynomial names" may sometimes look like binomials, but are different. For example, Gerard's herbal describes various kinds of spiderwort: "The first is called Phalangium ramosum, Branched Spiderwort.
The other... is aptly termed Phalangium Ephemerum Virginianum, Soon-Fading Spiderwort of Virginia". The Latin phrases are short descriptions, rather than identifying labels; the Bauhins, in particular Caspar Bauhin, took some important steps towards the binomial system, by pruning the Latin descriptions, in many cases to two words. The adoption by biologists of a system of binomial nomenclature is due to Swedish botanist and physician Carl von Linné, more known by his Latinized name Carl Linnaeus, it was in his 1753 Species Plantarum that he first began using a one-word "trivial name" together with a generic name in a system of binomial nomenclature. This trivial name is what is now known as specific name; the Bauhins' genus names were retained in many of these, but the descriptive part was reduced to a single word. Linnaeus's trivial names introduced an important new idea, namely that the function of a name could be to give a species a unique label; this meant. Thus Gerard's Phalangium ephemerum virginianum became Tradescantia virgi
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