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47-910: See text Taxus is a genus of coniferous trees or shrubs known as yews in the family Taxaceae . Yews occur around the globe in temperate zones of the northern hemisphere, northernmost in Norway and southernmost in the South Celebes . Some populations exist in tropical highlands. The oldest known fossil species are from the Early Cretaceous. They are relatively slow-growing and can be very long-lived, and reach heights of 2.5–20 m (8.2–65.6 ft), with trunk girth averaging 5 m (16 ft). They have reddish bark , lanceolate, flat, dark-green leaves 10–40 mm ( 1 ⁄ 2 – 1 + 1 ⁄ 2  in) long and 2–3 mm ( 3 ⁄ 32 – 1 ⁄ 8  in) broad, arranged spirally on

94-557: 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 ,

141-556: A given time (introduced over a hundred years ago), while the second, amphinaturalised or eurynaturalised , implies a notion of spatial extension (taxon assimilated indigenous and present over a vast space, opposed to stenonaturalised ). The degrees of naturalisation are defined in relation to the status of nativity or introduction of taxons or species: Animal naturalisation is mainly carried out through breeding and by commensalism following human migrations . The concerned species are thus: It sometimes happens that

188-643: 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

235-621: 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,

282-643: A major source of adventive populations. In botany , naturalisation is the situation in which an exogenous plant reproduces and disperses on its own in a new environment . For example, northern white cedar is naturalised in the United Kingdom, where it reproduces on its own, while it is not in France, where human intervention via cuttings or seeds are essential for its dissemination. Two categories of naturalisation are defined from two distinct parameters: one, archaeonaturalised , refers to introduction before

329-619: A naturalised species hybridizes with a native. The introduction site or introduction area is the place or, in a broadlier way, the new environment where the candidate species for naturalisation takes root. It is generally opposed to the origin area , where this same species is native. There is also a more ambiguous notion that is the "natural distribution area" or "natural distribution range", particularly when it comes to anthropophilic species or some species benefiting from anthropogenic land settlement (canals, bridges, deforestation, etc.) that have connected two previously isolated areas (e.g.

376-409: 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

423-438: A single seed 4–7 mm ( 5 ⁄ 32 – 9 ⁄ 32  in) long partly surrounded by a modified scale which develops into a soft, bright red berry -like structure called an aril , 8–15 mm ( 5 ⁄ 16 – 19 ⁄ 32  in) long and wide and open at the end. The arils are mature 6–9 months after pollination, and with the seed contained are eaten by thrushes , waxwings and other birds , which disperse

470-427: 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. ;

517-455: 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

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564-531: Is also relatively distinct with foliage intermediate between Sumatran yew and the other species. The Florida yew, Mexican yew and Pacific yew are all rare species listed as threatened or endangered. Yews typically occur in the understory or canopy of moist temperate or tropical mountain forests. Elevation varies by latitude from 3,000 m (9,800 ft) in tropical forests to near sea level in its northernmost populations. Yews are common in landscape architecture, giving rise to widespread naturalized populations in

611-596: 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

658-460: 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,

705-474: 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

752-562: The European rabbit , native to Europe and which abounds in Australia; or the Japanese knotweed which is invading Europe and America where it is considered to be amongst the one hundred most invasive species in the 21st century. Apart from direct competition between native and introduced populations, genetic pollution by hybridization can add up cumulatively to environmental effects that compromise

799-621: 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

846-799: 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;

893-570: The Suez Canal , which causes Lessepsian migration ). Naturalisation is sometimes done with human help in order to replace another species having suffered directly or indirectly from anthropogenic activities, or deemed less profitable for human use. Naturalised species may become invasive species if they become sufficiently abundant to have an adverse effect on native species (e.g. microbes affected by invasive plants ) or on biotope. Examples of naturalised species that have become invasive include

940-862: The Western Himalaya and Taxus sumatrana in Malesia are now generally agreed upon, but overlapping ranges in the Eastern Himalaya , China , and subtropical southeast Asia have led to greater confusion, with the species Taxus chinensis , Taxus mairei , and Taxus wallichiana being elucidated only in the 21st century with the aid of molecular phylogenetics . The most distinct is the Sumatran yew ( T. sumatrana , native to Sumatra and Celebes north to southernmost China ), distinguished by its sparse, sickle-shaped yellow-green leaves. The Mexican yew ( Taxus globosa , native to eastern Mexico south to Honduras )

987-404: 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,

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1034-469: 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

1081-791: The Scythians used its wood to make their bows. All of the yews are very closely related to each other, and some botanists treat them all as subspecies or varieties of just one widespread species; under this treatment, the species name used is Taxus baccata , the first yew described scientifically. Taxus species appear similar. Attempts at taxonomy vary from describing all yews as subspecies of T. baccata , as did RKF Pilger in 1903, to splitting species by even very small morphological differences, as did R. W. Spjut in 2007 with 25 species and over 50 varieties. Some species have traditionally been recognized by geographic distribution, but Asian species have been more difficult to classify. Taxus contorta in

1128-552: The United States. There, both T. baccata and Taxus cuspidata are common ornamental shrubs. T. baccata appears throughout Europe and into western Asia. T. cuspidata occurs over much of East Asia, in China, Japan, Korea, and Sakhalin . Taxus brevifolia ranges in the United States from California to Montana and Alaska, while Taxus canadensis appears in the northeastern United States and southeast Canada. Plants of

1175-1079: The World Online recognizes 12 confirmed species: Fossil (extinct) species Commonly reported hybrids Below are cladograms showing the evolutionary relationships between yew species and their global distribution. Austrotaxus Pseudotaxus T. brevifolia T. globosa T. floridana T. canadensis T. cuspidata T. contorta T. baccata T. wallichiana T. Huangshan type           T. chinensis T. phytonii T. calcicola T. mairei T. brevifolia T. floridana T. globosa T. wallichiana T. chinensis      T. florinii T. calcicola T. phytonii T. sumatrana T. canadensis T. cuspidata T. baccata T. mairei T. contorta T. fuana All species of yew contain highly poisonous taxine alkaloids , with some variation in

1222-442: 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

1269-422: The conservation of native populations. Some naturalised species, such as palms, can act as ecosystem engineers , by changing the habitat and creating new niches that can sometimes have positive effects on an ecosystem. Potential and/or perceived positive impacts of naturalised species are less studied than potential and/or perceived negative impacts. However, the impact on local species is not easy to assess in

1316-491: The exact formula of the alkaloid between the species. All parts of the tree except the arils contain the alkaloid. The arils are edible and sweet, but the seed is dangerously poisonous ; unlike birds, the human stomach can break down the seed coat and release the toxins into the body. This can have fatal results if yew 'berries' are eaten without removing the seeds first. Grazing animals, particularly cattle and horses , are also sometimes found dead near yew trees after eating

1363-406: The exception of the yew berries (which however contain a toxic seed); additionally, male and dioecious yews in this genus release cytotoxic pollen, which can cause headaches, lethargy, aching joints, itching, and skin rashes; it is also a trigger for asthma. These pollen granules are extremely small, and can easily pass through window screens. Male yews bloom and release abundant amounts of pollen in

1410-446: 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

1457-727: 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,

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1504-513: The hard seeds undamaged in their droppings; maturation of the arils is spread over 2–3 months, increasing the chances of successful seed dispersal. Taxus is the Latin word for this tree and its wood that is used to make javelins . The Latin word is probably borrowed, via Greek τόξον tóxon , from taxša , the Scythian word used for "yew" and "bow" (cognate of Persian تخش Taxš meaning bow) because

1551-432: 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

1598-628: 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,

1645-412: The leaves, though deer are able to break down the poisons and will eat yew foliage freely. In the wild, deer browsing of yews is often so extensive that wild yew trees are commonly restricted to cliffs and other steep slopes inaccessible to deer. The foliage is also eaten by the larvae of some Lepidopteran insects including the moth willow beauty . All parts of a yew plant are toxic to humans with

1692-522: 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. Naturalisation (biology) Naturalisation (or naturalization ) is the ecological phenomenon through which a species , taxon , or population of exotic (as opposed to native ) origin integrates into a given ecosystem , becoming capable of reproducing and growing in it, and proceeds to disseminate spontaneously. In some instances,

1739-403: 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

1786-428: 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

1833-502: The presence of a species in a given ecosystem is so ancient that it cannot be presupposed whether it is native or introduced. Generally, any introduced species may (in the wild) either go extinct or naturalise in its new environment. Some populations do not sustain themselves reproductively, but exist because of continued influx from elsewhere. Such a non-sustaining population, or the individuals within it, are said to be adventive . Cultivated plants, sometimes called nativars , are

1880-526: 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

1927-497: 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,

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1974-583: The spring; completely female yews only trap pollen while producing none. Yews in this genus are primarily separate-sexed, and males are extremely allergenic, with an OPALS allergy scale rating of 10 out of 10. Completely female yews have an OPALS rating of 1, and are considered "allergy-fighting". 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

2021-412: 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

2068-409: The stem, but with the leaf bases twisted to align the leaves in two flat rows either side of the stem. The male cones are globose, 3–6 mm ( 1 ⁄ 8 – 1 ⁄ 4  in) across, and shed their pollen in early spring. Yews are mostly dioecious , but occasional individuals can be variably monoecious , or change sex with time. The seed cones are highly modified, each cone containing

2115-403: 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

2162-566: 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

2209-429: 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

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