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53-506: Zea is a genus of flowering plants in the grass family . The best-known species is Z. mays (variously called maize , corn, or Indian corn), one of the most important crops for human societies throughout much of the world. The four wild species are commonly known as teosintes and are native to Mesoamerica . Zea is derived from the Greek name ( ζειά ) for another cereal grain (possibly spelt ). The five accepted species names in

106-557: A species : see Botanical name and Specific name (zoology) . The rules for the scientific names of organisms are laid down in the nomenclature codes , which allow each species a single unique name that, for animals (including protists ), plants (also including algae and fungi ) and prokaryotes ( bacteria and archaea ), is Latin and binomial in form; this contrasts with common or vernacular names , which are non-standardized, can be non-unique, and typically also vary by country and language of usage. Except for viruses ,

159-589: A dilute solution of hydrogen peroxide. Maize is a grass, related to sorghum and more distantly to rice and wheat . The genus Zea is closely related to Tripsacum , gamagrass. various grasses e.g. fescue , ryegrass Hordeum (barley) Triticum (wheat) Oryza (rice) Pennisetum (fountaingrasses, pearl millet ) Sorghum (sorghum) Tripsacum (gamagrass) Zea mays (maize) other Zea species ( teosintes ) Teosintes are critical components of maize domestication , but opinions vary about which taxa were involved. According to

212-588: A dilute solution of hydrogen peroxide. Maize is a grass, related to sorghum and more distantly to rice and wheat . The genus Zea is closely related to Tripsacum , gamagrass. various grasses e.g. fescue , ryegrass Hordeum (barley) Triticum (wheat) Oryza (rice) Pennisetum (fountaingrasses, pearl millet ) Sorghum (sorghum) Tripsacum (gamagrass) Zea mays (maize) other Zea species ( teosintes ) Teosintes are critical components of maize domestication , but opinions vary about which taxa were involved. According to

265-431: A large amount of scientific interest exists in conferring beneficial teosinte traits, such as nitrogen fixation, insect resistance, perennialism, and flood tolerance, to cultivated maize lines, although this is very difficult due to linked deleterious teosinte traits. Gene flow from genetically modified maize to teosinte weeds has only been observed to produce a GM teosinte with the same trait but this may not always be

318-430: A large amount of scientific interest exists in conferring beneficial teosinte traits, such as nitrogen fixation, insect resistance, perennialism, and flood tolerance, to cultivated maize lines, although this is very difficult due to linked deleterious teosinte traits. Gene flow from genetically modified maize to teosinte weeds has only been observed to produce a GM teosinte with the same trait but this may not always be

371-651: A later homonym of a validly published name is a nomen illegitimum or nom. illeg. ; for a full list refer to the International Code of Nomenclature for algae, fungi, and plants and the work cited above by Hawksworth, 2010. In place of the "valid taxon" in zoology, the nearest equivalent in botany is " correct name " or "current name" which can, again, differ or change with alternative taxonomic treatments or new information that results in previously accepted genera being combined or split. Prokaryote and virus codes of nomenclature also exist which serve as

424-628: A long time and redescribed as new by a range of subsequent workers, or if a range of genera previously considered separate taxa have subsequently been consolidated into one. For example, the World Register of Marine Species presently lists 8 genus-level synonyms for the sperm whale genus Physeter Linnaeus, 1758, and 13 for the bivalve genus Pecten O.F. Müller, 1776. Within the same kingdom, one generic name can apply to one genus only. However, many names have been assigned (usually unintentionally) to two or more different genera. For example,

477-639: A morphology rather like Z. m. parviglumis with many terminal chromosome knobs and an isozyme position between the two sections. Considered to be phenotypically the most distinctive, as well as the most threatened, teosinte is Zea nicaraguensis . This teosinte thrives in flooded conditions along 200 m of a coastal estuarine river in northwest Nicaragua. Teosintes strongly resemble maize in many ways, notably their tassel (male inflorescence) morphology. Teosintes are distinguished from maize most obviously by their numerous branches each bearing bunches of distinctive, small female inflorescences . These spikes mature to form

530-409: A reference for designating currently accepted genus names as opposed to others which may be either reduced to synonymy, or, in the case of prokaryotes, relegated to a status of "names without standing in prokaryotic nomenclature". An available (zoological) or validly published (botanical) name that has been historically applied to a genus but is not regarded as the accepted (current/valid) name for

583-427: A taxon; however, the names published in suppressed works are made unavailable via the relevant Opinion dealing with the work in question. In botany, similar concepts exist but with different labels. The botanical equivalent of zoology's "available name" is a validly published name . An invalidly published name is a nomen invalidum or nom. inval. ; a rejected name is a nomen rejiciendum or nom. rej. ;

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636-455: A total of c. 520,000 published names (including synonyms) as at end 2019, increasing at some 2,500 published generic names per year. "Official" registers of taxon names at all ranks, including genera, exist for a few groups only such as viruses and prokaryotes, while for others there are compendia with no "official" standing such as Index Fungorum for fungi, Index Nominum Algarum and AlgaeBase for algae, Index Nominum Genericorum and

689-485: A two-ranked 'ear' of five to 10 triangular or trapezoidal, black or brown disarticulating segments, each with one seed. Each seed is enclosed by a very hard fruitcase, consisting of a cupule or depression in the rachis and a tough lower glume. This protects them from the digestive processes of ruminants that forage on teosinte and aid in seed distribution through their droppings. Teosinte seed exhibits some resistance to germination, but will quickly germinate if treated with

742-485: A two-ranked 'ear' of five to 10 triangular or trapezoidal, black or brown disarticulating segments, each with one seed. Each seed is enclosed by a very hard fruitcase, consisting of a cupule or depression in the rachis and a tough lower glume. This protects them from the digestive processes of ruminants that forage on teosinte and aid in seed distribution through their droppings. Teosinte seed exhibits some resistance to germination, but will quickly germinate if treated with

795-612: Is discouraged by both the International Code of Zoological Nomenclature and the International Code of Nomenclature for algae, fungi, and plants , there are some five thousand such names in use in more than one kingdom. For instance, A list of generic homonyms (with their authorities), including both available (validly published) and selected unavailable names, has been compiled by the Interim Register of Marine and Nonmarine Genera (IRMNG). The type genus forms

848-460: Is somewhat arbitrary. Although all species within a genus are supposed to be "similar", there are no objective criteria for grouping species into genera. There is much debate among zoologists about whether enormous, species-rich genera should be maintained, as it is extremely difficult to come up with identification keys or even character sets that distinguish all species. Hence, many taxonomists argue in favor of breaking down large genera. For instance,

901-474: Is the type species , and the generic name is permanently associated with the type specimen of its type species. Should the specimen turn out to be assignable to another genus, the generic name linked to it becomes a junior synonym and the remaining taxa in the former genus need to be reassessed. In zoological usage, taxonomic names, including those of genera, are classified as "available" or "unavailable". Available names are those published in accordance with

954-508: Is typified by dark-staining knobs made up of heterochromatin that are terminal on most chromosome arms, while most subspecies of section Zea may have none to three knobs between each chromosome end and the centromere and very few terminal knobs (except Z. m. huehuetenangensis , which has many large terminal knobs). Both annual and perennial teosinte species occur. Z. diploperennis and Z. perennis are perennial, while all other species are annual. All species are diploid (n=10) with

1007-530: The European corn borer ( Ostrinia nubilalis ), among many others. Virtually all populations of teosintes are either threatened or endangered: Z. diploperennis exists in an area of only a few square miles; Z. nicaraguensis survives as about 6000 plants in an area of 200 × 150 m. The Mexican and Nicaraguan governments have taken action in recent years to protect wild teosinte populations, using both in situ and ex situ conservation methods. Currently,

1060-475: The European corn borer ( Ostrinia nubilalis ), among many others. Virtually all populations of teosintes are either threatened or endangered: Z. diploperennis exists in an area of only a few square miles; Z. nicaraguensis survives as about 6000 plants in an area of 200 × 150 m. The Mexican and Nicaraguan governments have taken action in recent years to protect wild teosinte populations, using both in situ and ex situ conservation methods. Currently,

1113-621: The International Code of Zoological Nomenclature ; the earliest such name for any taxon (for example, a genus) should then be selected as the " valid " (i.e., current or accepted) name for the taxon in question. Consequently, there will be more available names than valid names at any point in time; which names are currently in use depending on the judgement of taxonomists in either combining taxa described under multiple names, or splitting taxa which may bring available names previously treated as synonyms back into use. "Unavailable" names in zoology comprise names that either were not published according to

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1166-824: The International Plant Names Index for plants in general, and ferns through angiosperms, respectively, and Nomenclator Zoologicus and the Index to Organism Names for zoological names. Totals for both "all names" and estimates for "accepted names" as held in the Interim Register of Marine and Nonmarine Genera (IRMNG) are broken down further in the publication by Rees et al., 2020 cited above. The accepted names estimates are as follows, broken down by kingdom: The cited ranges of uncertainty arise because IRMNG lists "uncertain" names (not researched therein) in addition to known "accepted" names;

1219-651: The centromere and very few terminal knobs (except Z. m. huehuetenangensis , which has many large terminal knobs). Both annual and perennial teosinte species occur. Z. diploperennis and Z. perennis are perennial, while all other species are annual. All species are diploid (n=10) with the exception of Z. perennis , which is tetraploid (n=20). The different species and subspecies of teosinte can be readily distinguished based on morphological, cytogenetic, protein, and DNA differences and on geographic origin. The two perennials are sympatric and very similar and some consider them to be one species. What many consider to be

1272-516: The genus are: Maize ( Zea mays ) is further divided into four subspecies: Z. m. huehuetenangensis , Z. m. mexicana , Z. m. parviglumis (Balsas teosinte, the ancestor of maize), and Z. m. mays . The first three subspecies are teosintes; the last is maize , or corn, the only domesticated taxon in the genus Zea . The genus is divided into two sections : Luxuriantes , with Z. diploperennis , Z. luxurians , Z. nicaraguensis , Z. perennis ; and Zea with Z. mays . The former section

1325-560: The larvae ( caterpillars ) of some Lepidopteran species including (in the Americas) the fall armyworm ( Spodoptera frugiperda ), the corn earworm ( Helicoverpa zea ), and the stem borers Diatraea and Chilo ; in the Old World, it is attacked by the double-striped pug , the cutworms heart and club and heart and dart , Hypercompe indecisa , the rustic shoulder-knot , the setaceous Hebrew character and turnip moths , and

1378-447: The larvae ( caterpillars ) of some Lepidopteran species including (in the Americas) the fall armyworm ( Spodoptera frugiperda ), the corn earworm ( Helicoverpa zea ), and the stem borers Diatraea and Chilo ; in the Old World, it is attacked by the double-striped pug , the cutworms heart and club and heart and dart , Hypercompe indecisa , the rustic shoulder-knot , the setaceous Hebrew character and turnip moths , and

1431-404: The platypus belongs to the genus Ornithorhynchus although George Shaw named it Platypus in 1799 (these two names are thus synonyms ) . However, the name Platypus had already been given to a group of ambrosia beetles by Johann Friedrich Wilhelm Herbst in 1793. A name that means two different things is a homonym . Since beetles and platypuses are both members of the kingdom Animalia,

1484-473: The French botanist Joseph Pitton de Tournefort (1656–1708) is considered "the founder of the modern concept of genera". The scientific name (or the scientific epithet) of a genus is also called the generic name ; in modern style guides and science, it is always capitalised. It plays a fundamental role in binomial nomenclature , the system of naming organisms , where it is combined with the scientific name of

1537-557: The ancestor of maize), and Z. m. mays . The first three subspecies are teosintes; the last is maize , or corn, the only domesticated taxon in the genus Zea . The genus is divided into two sections : Luxuriantes , with Z. diploperennis , Z. luxurians , Z. nicaraguensis , Z. perennis ; and Zea with Z. mays . The former section is typified by dark-staining knobs made up of heterochromatin that are terminal on most chromosome arms, while most subspecies of section Zea may have none to three knobs between each chromosome end and

1590-504: The available early maize gene pool can be divided into three clusters: Also, some other intermediate genomes, or admixtures of these clusters occur. According to these authors, "The maize of the Andes Mountains with its distinctive hand grenade-shaped ears was derived from the maize of lowland South America, which in turn came from maize of the lowlands of Guatemala and southern Mexico." Zea species are used as food plants by

1643-438: The available early maize gene pool can be divided into three clusters: Also, some other intermediate genomes, or admixtures of these clusters occur. According to these authors, "The maize of the Andes Mountains with its distinctive hand grenade-shaped ears was derived from the maize of lowland South America, which in turn came from maize of the lowlands of Guatemala and southern Mexico." Zea species are used as food plants by

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1696-442: The base for higher taxonomic ranks, such as the family name Canidae ("Canids") based on Canis . However, this does not typically ascend more than one or two levels: the order to which dogs and wolves belong is Carnivora ("Carnivores"). The numbers of either accepted, or all published genus names is not known precisely; Rees et al., 2020 estimate that approximately 310,000 accepted names (valid taxa) may exist, out of

1749-422: The exception of Z. perennis , which is tetraploid (n=20). The different species and subspecies of teosinte can be readily distinguished based on morphological, cytogenetic, protein, and DNA differences and on geographic origin. The two perennials are sympatric and very similar and some consider them to be one species. What many consider to be the most puzzling teosinte is Z. m. huehuetenangensis , which combines

1802-489: The fields, but the rate of gene exchange is quite low. Some populations of Z. m. mexicana display Vavilovian mimicry within cultivated maize fields, having evolved a maize-like form as a result of the farmers' selective weeding pressure. In some areas of Mexico , teosintes are regarded by maize farmers as a noxious weed , while in a few areas, farmers regard it as a beneficial companion plant , and encourage its introgression into their maize. According to Matsuoka et al.,

1855-489: The fields, but the rate of gene exchange is quite low. Some populations of Z. m. mexicana display Vavilovian mimicry within cultivated maize fields, having evolved a maize-like form as a result of the farmers' selective weeding pressure. In some areas of Mexico , teosintes are regarded by maize farmers as a noxious weed , while in a few areas, farmers regard it as a beneficial companion plant , and encourage its introgression into their maize. According to Matsuoka et al.,

1908-446: The form "author, year" in zoology, and "standard abbreviated author name" in botany. Thus in the examples above, the genus Canis would be cited in full as " Canis Linnaeus, 1758" (zoological usage), while Hibiscus , also first established by Linnaeus but in 1753, is simply " Hibiscus L." (botanical usage). Each genus should have a designated type , although in practice there is a backlog of older names without one. In zoology, this

1961-737: The generic name (or its abbreviated form) still forms the leading portion of the scientific name, for example, Canis lupus lupus for the Eurasian wolf subspecies, or as a botanical example, Hibiscus arnottianus ssp. immaculatus . Also, as visible in the above examples, the Latinised portions of the scientific names of genera and their included species (and infraspecies, where applicable) are, by convention, written in italics . The scientific names of virus species are descriptive, not binomial in form, and may or may not incorporate an indication of their containing genus; for example,

2014-432: The idea that a newly defined genus should fulfill these three criteria to be descriptively useful: Moreover, genera should be composed of phylogenetic units of the same kind as other (analogous) genera. The term "genus" comes from Latin genus , a noun form cognate with gignere ('to bear; to give birth to'). The Swedish taxonomist Carl Linnaeus popularized its use in his 1753 Species Plantarum , but

2067-633: The largest component, with 23,236 ± 5,379 accepted genus names, of which 20,845 ± 4,494 are angiosperms (superclass Angiospermae). By comparison, the 2018 annual edition of the Catalogue of Life (estimated >90% complete, for extant species in the main) contains currently 175,363 "accepted" genus names for 1,744,204 living and 59,284 extinct species, also including genus names only (no species) for some groups. The number of species in genera varies considerably among taxonomic groups. For instance, among (non-avian) reptiles , which have about 1180 genera,

2120-413: The lizard genus Anolis has been suggested to be broken down into 8 or so different genera which would bring its ~400 species to smaller, more manageable subsets. Teosinte Zea is a genus of flowering plants in the grass family . The best-known species is Z. mays (variously called maize , corn, or Indian corn), one of the most important crops for human societies throughout much of

2173-403: The most (>300) have only 1 species, ~360 have between 2 and 4 species, 260 have 5–10 species, ~200 have 11–50 species, and only 27 genera have more than 50 species. However, some insect genera such as the bee genera Lasioglossum and Andrena have over 1000 species each. The largest flowering plant genus, Astragalus , contains over 3,000 species. Which species are assigned to a genus

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2226-711: The most puzzling teosinte is Z. m. huehuetenangensis , which combines a morphology rather like Z. m. parviglumis with many terminal chromosome knobs and an isozyme position between the two sections. Considered to be phenotypically the most distinctive, as well as the most threatened, teosinte is Zea nicaraguensis . This teosinte thrives in flooded conditions along 200 m of a coastal estuarine river in northwest Nicaragua. Teosintes strongly resemble maize in many ways, notably their tassel (male inflorescence) morphology. Teosintes are distinguished from maize most obviously by their numerous branches each bearing bunches of distinctive, small female inflorescences . These spikes mature to form

2279-508: The most widely held evolutionary model, the crop was derived directly from Z. m. parviglumis by selection of key mutations; but in some varieties up to 20% of its genetic material came from Z. m. mexicana through introgression . All but the Nicaraguan species of teosinte may grow in or very near corn fields, providing opportunities for introgression between teosinte and maize. First, and later-generation hybrids are often found in

2332-448: The most widely held evolutionary model, the crop was derived directly from Z. m. parviglumis by selection of key mutations; but in some varieties up to 20% of its genetic material came from Z. m. mexicana through introgression . All but the Nicaraguan species of teosinte may grow in or very near corn fields, providing opportunities for introgression between teosinte and maize. First, and later-generation hybrids are often found in

2385-428: The name could not be used for both. Johann Friedrich Blumenbach published the replacement name Ornithorhynchus in 1800. However, a genus in one kingdom is allowed to bear a scientific name that is in use as a generic name (or the name of a taxon in another rank) in a kingdom that is governed by a different nomenclature code. Names with the same form but applying to different taxa are called "homonyms". Although this

2438-411: The outcome. Teosinte with a different insertion of the transgene may result and functionally different outcomes may be produced. Genus The composition of a genus is determined by taxonomists . The standards for genus classification are not strictly codified, so different authorities often produce different classifications for genera. There are some general practices used, however, including

2491-541: The provisions of the ICZN Code, e.g., incorrect original or subsequent spellings, names published only in a thesis, and generic names published after 1930 with no type species indicated. According to "Glossary" section of the zoological Code, suppressed names (per published "Opinions" of the International Commission of Zoological Nomenclature) remain available but cannot be used as the valid name for

2544-497: The specific name particular to the wolf. A botanical example would be Hibiscus arnottianus , a particular species of the genus Hibiscus native to Hawaii. The specific name is written in lower-case and may be followed by subspecies names in zoology or a variety of infraspecific names in botany . When the generic name is already known from context, it may be shortened to its initial letter, for example, C. lupus in place of Canis lupus . Where species are further subdivided,

2597-412: The standard format for a species name comprises the generic name, indicating the genus to which the species belongs, followed by the specific epithet, which (within that genus) is unique to the species. For example, the gray wolf 's scientific name is Canis lupus , with Canis ( Latin for 'dog') being the generic name shared by the wolf's close relatives and lupus (Latin for 'wolf') being

2650-403: The taxon is termed a synonym ; some authors also include unavailable names in lists of synonyms as well as available names, such as misspellings, names previously published without fulfilling all of the requirements of the relevant nomenclatural code, and rejected or suppressed names. A particular genus name may have zero to many synonyms, the latter case generally if the genus has been known for

2703-576: The values quoted are the mean of "accepted" names alone (all "uncertain" names treated as unaccepted) and "accepted + uncertain" names (all "uncertain" names treated as accepted), with the associated range of uncertainty indicating these two extremes. Within Animalia, the largest phylum is Arthropoda , with 151,697 ± 33,160 accepted genus names, of which 114,387 ± 27,654 are insects (class Insecta). Within Plantae, Tracheophyta (vascular plants) make up

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2756-429: The virus species " Salmonid herpesvirus 1 ", " Salmonid herpesvirus 2 " and " Salmonid herpesvirus 3 " are all within the genus Salmonivirus ; however, the genus to which the species with the formal names " Everglades virus " and " Ross River virus " are assigned is Alphavirus . As with scientific names at other ranks, in all groups other than viruses, names of genera may be cited with their authorities, typically in

2809-408: The world. The four wild species are commonly known as teosintes and are native to Mesoamerica . Zea is derived from the Greek name ( ζειά ) for another cereal grain (possibly spelt ). The five accepted species names in the genus are: Maize ( Zea mays ) is further divided into four subspecies: Z. m. huehuetenangensis , Z. m. mexicana , Z. m. parviglumis (Balsas teosinte,

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