''Taxus'' is a
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
of
coniferous
Conifers are a group of cone-bearing seed plants, a subset of gymnosperms. Scientifically, they make up the division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single extant class, Pinopsida. All extant ...
tree
In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are ...
s or
shrub
A shrub (often also called a bush) is a small-to-medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees ...
s known as yews in the family
Taxaceae
Taxaceae (), commonly called the yew family, is a coniferous family which includes six extant and two extinct genera, and about 30 species of plants, or in older interpretations three genera and 7 to 12 species.
Description
They are many-bran ...
. They are relatively slow-growing and can be very long-lived, and reach heights of , with trunk girth averaging . They have reddish
bark, lanceolate, flat, dark-green
leaves
A leaf (plural, : leaves) is any of the principal appendages of a vascular plant plant stem, stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", wh ...
long and broad, arranged spirally on the stem, but with the leaf bases twisted to align the leaves in two flat rows either side of the stem.
The oldest known fossil species are from the Early Cretaceous.
Morphology
The
seed cones
A conifer cone (in formal botanical usage: strobilus, plural strobili) is a seed-bearing organ on gymnosperm plants. It is usually woody, ovoid to globular, including scales and bracts arranged around a central axis, especially in conifers an ...
are highly modified, each cone containing a single
seed
A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiospe ...
long partly surrounded by a modified scale which develops into a soft, bright red
berry
A berry is a small, pulpy, and often edible fruit. Typically, berries are juicy, rounded, brightly colored, sweet, sour or tart, and do not have a stone or pit, although many pips or seeds may be present. Common examples are strawberries, raspb ...
-like structure called an
aril
An aril (pronounced ), also called an arillus, is a specialized outgrowth from a seed that partly or completely covers the seed. An arillode or false aril is sometimes distinguished: whereas an aril grows from the attachment point of the see ...
, 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
The thrushes are a passerine bird family, Turdidae, with a worldwide distribution. The family was once much larger before biologists reclassified the former subfamily Saxicolinae, which includes the chats and European robins, as Old World flycat ...
,
waxwing
The waxwings are three species of passerine birds classified in the genus ''Bombycilla''. They are pinkish-brown and pale grey with distinctive smooth plumage in which many body feathers are not individually visible, a black and white eyestripe, ...
s and other
bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweigh ...
s, which disperse the hard seeds undamaged in their droppings; maturation of the arils is spread over 2–3 months, increasing the chances of successful seed dispersal. The male cones are globose, across, and shed their
pollen
Pollen is a powdery substance produced by seed plants. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cells). Pollen grains have a hard coat made of sporopollenin that protects the gametophyt ...
in early spring. Yews are mostly
dioecious
Dioecy (; ; adj. dioecious , ) is a characteristic of a species, meaning that it has distinct individual organisms (unisexual) that produce male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproductio ...
, but occasional individuals can be variably
monoecious
Monoecy (; adj. monoecious ) is a sexual system in seed plants where separate male and female cones or flowers are present on the same plant. It is a monomorphic sexual system alongside gynomonoecy, andromonoecy and trimonoecy.
Monoecy is conne ...
, or change sex with time.
Taxonomy
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
''Taxus baccata'' is a species of evergreen tree in the family Taxaceae, native to western, central and southern Europe (including Britain and Ireland), northwest Africa, northern Iran, and southwest Asia.Rushforth, K. (1999). ''Trees of Britain ...
'', the first yew described scientifically. Other sources, however, recognize 9 species, for example th
Plant List
''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. ''T. contorta'' in the
Western Himalaya
The Western Himalayas refers to the western half of the Himalayas, in northern Pakistan and northwestern India. It is also known as the Punjab Himalayas. Four of the five tributaries of the Indus River in Punjab (Beas, Chenab, Jhelum, and Ravi) r ...
and ''T. sumatrana'' in
Malesia
Malesia is a biogeographical region straddling the Equator and the boundaries of the Indomalayan and Australasian realms, and also a phytogeographical floristic region in the Paleotropical Kingdom. It has been given different definitions. The ...
are now generally agreed upon, but overlapping ranges in the
Eastern Himalaya
]
The Eastern Himalayas extend from eastern Nepal across Northeast India, Bhutan, the Tibet Autonomous Region to Yunnan in China and northern Myanmar. The climate of this region is influenced by the monsoon of South Asia from June to September. It ...
,
China
China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...
, and subtropical southeast Asia have led to greater confusion, with the species ''T. chinensis'', ''T. mairei'', and ''T. wallichiana'' being elucidated only in the 21st century with the aid of
molecular phylogenetics
Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...
.
The most distinct is the Sumatran yew (''T. sumatrana'', native to
Sumatra
Sumatra is one of the Sunda Islands of western Indonesia. It is the largest island that is fully within Indonesian territory, as well as the sixth-largest island in the world at 473,481 km2 (182,812 mi.2), not including adjacent i ...
and
Celebes
Sulawesi (), also known as Celebes (), is an island in Indonesia. One of the four Greater Sunda Islands, and the world's eleventh-largest island, it is situated east of Borneo, west of the Maluku Islands, and south of Mindanao and the Sulu A ...
north to southernmost
China
China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...
), distinguished by its sparse, sickle-shaped yellow-green leaves. The Mexican yew (''T. globosa'', native to eastern
Mexico
Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...
south to
Honduras
Honduras, officially the Republic of Honduras, is a country in Central America. The republic of Honduras is bordered to the west by Guatemala, to the southwest by El Salvador, to the southeast by Nicaragua, to the south by the Pacific Oce ...
) 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.
Toxicity
All species of yew contain highly
poison
Poison is a chemical substance that has a detrimental effect to life. The term is used in a wide range of scientific fields and industries, where it is often specifically defined. It may also be applied colloquially or figuratively, with a broa ...
ous
taxine
Taxine alkaloids, which are often named under the collective title of taxines, are the toxic chemicals that can be isolated from the yew tree. The amount of taxine alkaloids depends on the species of yew, with ''Taxus baccata'' and '' Taxus cusp ...
alkaloid
Alkaloids are a class of basic, naturally occurring organic compounds that contain at least one nitrogen atom. This group also includes some related compounds with neutral and even weakly acidic properties. Some synthetic compounds of similar ...
s, with some variation in the exact formula of the alkaloid between the species. All parts of the tree except the
aril
An aril (pronounced ), also called an arillus, is a specialized outgrowth from a seed that partly or completely covers the seed. An arillode or false aril is sometimes distinguished: whereas an aril grows from the attachment point of the see ...
s contain the alkaloid. The arils are edible and sweet, but the seed is dangerously
poison
Poison is a chemical substance that has a detrimental effect to life. The term is used in a wide range of scientific fields and industries, where it is often specifically defined. It may also be applied colloquially or figuratively, with a broa ...
ous; unlike birds, the
human
Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, culture, ...
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
Cattle (''Bos taurus'') are large, domesticated, cloven-hooved, herbivores. They are a prominent modern member of the subfamily Bovinae and the most widespread species of the genus ''Bos''. Adult females are referred to as cows and adult mal ...
and
horse
The horse (''Equus ferus caballus'') is a domesticated, one-toed, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two extant subspecies of ''Equus ferus''. The horse has evolved over the past 45 to 55 million y ...
s, are also sometimes found dead near yew trees after eating the leaves, though
deer
Deer or true deer are hoofed ruminant mammals forming the family Cervidae. The two main groups of deer are the Cervinae, including the muntjac, the elk (wapiti), the red deer, and the fallow deer; and the Capreolinae, including the reindeer ...
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
larva
A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle.
The ...
e of some
Lepidoptera
Lepidoptera ( ) is an order (biology), order of insects that includes butterfly, butterflies and moths (both are called lepidopterans). About 180,000 species of the Lepidoptera are described, in 126 Family (biology), families and 46 Taxonomic r ...
n
insect
Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pairs ...
s including the moth
willow beauty.
Distribution
Yews occur around the globe in temperate zones of the northern hemisphere, northernmost in
Norway
Norway, officially the Kingdom of Norway, is a Nordic country in Northern Europe, the mainland territory of which comprises the western and northernmost portion of the Scandinavian Peninsula. The remote Arctic island of Jan Mayen and t ...
and southernmost in the
South Celebes
South Sulawesi ( id, Sulawesi Selatan) is a province in the southern peninsula of Sulawesi. The Selayar Islands archipelago to the south of Sulawesi is also part of the province. The capital is Makassar. The province is bordered by Central Sulawe ...
. Some populations exist in tropical highlands. Yews typically occur in the understory or canopy of moist temperate or tropical mountain forests. Elevation varies by latitude from in tropical forests to near sea level in its northernmost populations.
Yews are common in landscape architecture, giving rise to widespread
naturalized
Naturalization (or naturalisation) is the legal act or process by which a non-citizen of a country may acquire citizenship or nationality of that country. It may be done automatically by a statute, i.e., without any effort on the part of the in ...
populations in the United States. There, both ''T. baccata'' and ''T. 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
Sakhalin ( rus, Сахали́н, r=Sakhalín, p=səxɐˈlʲin; ja, 樺太 ''Karafuto''; zh, c=, p=Kùyèdǎo, s=库页岛, t=庫頁島; Manchu: ᠰᠠᡥᠠᠯᡳᠶᠠᠨ, ''Sahaliyan''; Orok: Бугата на̄, ''Bugata nā''; Nivkh: ...
.
''T. brevifolia'' ranges in the United States from California to Montana and Alaska,
while ''T. canadensis'' appears in the northeastern United States and southeast Canada.
Allergenic potential
All parts of a yew plant are toxic to humans with the exception of the yew berries (which however contain a toxic seed); additionally, male and dioecious yews in this genus release
cytotoxic
Cytotoxicity is the quality of being toxic to cells. Examples of toxic agents are an immune cell or some types of venom, e.g. from the puff adder (''Bitis arietans'') or brown recluse spider (''Loxosceles reclusa'').
Cell physiology
Treating cells ...
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 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
Optical Payload for Lasercomm Science (OPALS) is a spacecraft communication instrument developed at the Jet Propulsion Laboratory that was tested on the International Space Station (ISS) from 18 April 2014 to 17 July 2014 to demonstrate the te ...
allergy scale rating of 10 out of 10. Completely female yews have an OPALS rating of 1, and are considered "allergy-fighting".
Uses and traditions
Bows
Yew wood is reddish brown (with whiter sapwood), and is very springy. It was traditionally used to make bows, especially the
longbow
A longbow (known as warbow in its time, in contrast to a hunting bow) is a type of tall bow that makes a fairly long draw possible. A longbow is not significantly recurved. Its limbs are relatively narrow and are circular or D-shaped in cross ...
.
Latin taxus "yew tree," is probably borrowed, via Greek, from ''Taxša'', the
Scythian
The Scythians or Scyths, and sometimes also referred to as the Classical Scythians and the Pontic Scythians, were an ancient Eastern
* : "In modern scholarship the name 'Sakas' is reserved for the ancient tribes of northern and eastern Centra ...
word for yew (and bow) (cognate of
Persian
Persian may refer to:
* People and things from Iran, historically called ''Persia'' in the English language
** Persians, the majority ethnic group in Iran, not to be conflated with the Iranic peoples
** Persian language, an Iranian language of the ...
تخش ''Taxš'', meaning bow).
British yews tend to be too gnarly, and thus the wood for English longbows used at the
Battle of Agincourt
The Battle of Agincourt ( ; french: Azincourt ) was an English victory in the Hundred Years' War. It took place on 25 October 1415 (Saint Crispin's Day) near Azincourt, in northern France. The unexpected English victory against the numerica ...
was imported from Spain or northern Italy.
Ötzi
Ötzi, also called the Iceman, is the natural mummy of a man who lived some time between 3350 and 3105 BC, discovered in September 1991 in the Ötztal Alps (hence the nickname "Ötzi") on the border between Austria and Italy.
Ötzi is believed to ...
, the Chalcolithic mummy found in 1991 in the Italian Alps, carried an unfinished bow made of yew wood. Consequently, it is not surprising that in
Norse mythology
Norse, Nordic, or Scandinavian mythology is the body of myths belonging to the North Germanic peoples, stemming from Old Norse religion and continuing after the Christianization of Scandinavia, and into the Nordic folklore of the modern period ...
, the abode of the god of the bow,
Ullr
In Norse mythology, Ullr (Old Norse: ) is a god associated with archery. Although literary attestations of Ullr are sparse, evidence including relatively ancient place-name evidence from Scandinavia suggests that he was a major god in earlier G ...
, had the name
Ydalir (Yew Dales). Most longbow wood used in northern Europe was imported from
Iberia
The Iberian Peninsula (),
**
* Aragonese and Occitan: ''Peninsula Iberica''
**
**
* french: Péninsule Ibérique
* mwl, Península Eibérica
* eu, Iberiar penintsula also known as Iberia, is a peninsula in southwestern Europe, defi ...
, where climatic conditions are better for growing the knot-free yew wood required. The yew longbow was the critical weapon used by the English in the defeat of the French
cavalry
Historically, cavalry (from the French word ''cavalerie'', itself derived from "cheval" meaning "horse") are soldiers or warriors who fight mounted on horseback. Cavalry were the most mobile of the combat arms, operating as light cavalry ...
at the Battle of Agincourt, 1415.
Cultivation
It is suggested that English
parish
A parish is a territorial entity in many Christian denominations, constituting a division within a diocese. A parish is under the pastoral care and clerical jurisdiction of a priest, often termed a parish priest, who might be assisted by one or m ...
es were required to grow yews and, because of the trees' toxic properties, they were grown in the only commonly enclosed area of a village – the churchyard. The yew tree can often be found in church graveyards and is symbolic of sadness. Such a representation appears in Lord Alfred Tennyson's poem "
In Memoriam A.H.H.
The poem "In Memoriam A.H.H." (1850) by Alfred, Lord Tennyson, is an elegy for his Cambridge friend Arthur Henry Hallam, who died of cerebral haemorrhage at the age of twenty-two years, in Vienna in 1833. As a sustained exercise in tetrametri ...
" (2.61–64).
The yew can be very long-lived. The
Fortingall Yew
The Fortingall Yew is an ancient European yew (''Taxus baccata'') in the churchyard of the village of Fortingall in Perthshire, Scotland. Considered one of the oldest trees in Britain, modern estimates place its age at an average of 5,000 years.
...
has been considered to be the oldest tree in Europe, at something over 2,000 years old. Tradition has it that
Pontius Pilate
Pontius Pilate (; grc-gre, Πόντιος Πιλᾶτος, ) was the fifth governor of the Roman province of Judaea, serving under Emperor Tiberius from 26/27 to 36/37 AD. He is best known for being the official who presided over the trial of J ...
slept under it while on duty before 30 AD. This has been topped by a tree in the churchyard of a small Welsh village called St Cynog. It has been dated to 5,000 years old by dendrologist Janis Fry. Such old trees usually consist of a circular ring of growths of yew, since their heart has long since rotted away.
The
Eihwaz
Eiwaz or Eihaz is the reconstructed Proto-Germanic name of the rune , coming from a word for " yew". Two variants of the word are reconstructed for Proto-Germanic, ''*īhaz'' (''*ē2haz'', from Proto-Indo-European '), continued in Old English as ...
rune
Runes are the letter (alphabet), letters in a set of related alphabets known as runic alphabets native to the Germanic peoples. Runes were used to write various Germanic languages (with some exceptions) before they adopted the Latin alphabet, a ...
is named after the yew, and sometimes also associated with the "evergreen"
world tree
The world tree is a motif present in several religions and mythologies, particularly Indo-European religions, Siberian religions, and Native American religions. The world tree is represented as a colossal tree which supports the heavens, thereb ...
,
Yggdrasil
Yggdrasil (from Old Norse ), in Norse cosmology, is an immense and central sacred tree. Around it exists all else, including the Nine Worlds.
Yggdrasil is attested in the ''Poetic Edda'' compiled in the 13th century from earlier traditional s ...
.
Horticulture
Yews are widely used in landscaping and ornamental
horticulture
Horticulture is the branch of agriculture that deals with the art, science, technology, and business of plant cultivation. It includes the cultivation of fruits, vegetables, nuts, seeds, herbs, sprouts, mushrooms, algae, flowers, seaweeds and no ...
. Over 400
cultivar
A cultivar is a type of cultivated plant that people have selected for desired traits and when propagated retain those traits. Methods used to propagate cultivars include: division, root and stem cuttings, offsets, grafting, tissue culture, ...
s of yews have been named, the vast majority of these being derived from European yew (''Taxus baccata'') or Japanese yew (''Taxus cuspidata''). The hybrid between these two species is
''Taxus'' × ''media''. A popular fastigiate selection of the European yew (''Taxus baccata'' 'Fastigiata') is often called the Irish yew, illustrating the difficulties with common names. A few cultivars with yellow leaves are collectively known as golden yews.
Chemistry
The
Pacific yew
''Taxus brevifolia'', the Pacific yew or western yew, is a species of tree in the yew family Taxaceae native to the Pacific Northwest of North America. It is a small evergreen conifer, thriving in moisture and otherwise tending to take the form o ...
(''Taxus brevifolia''), native to the
Pacific Northwest
The Pacific Northwest (sometimes Cascadia, or simply abbreviated as PNW) is a geographic region in western North America bounded by its coastal waters of the Pacific Ocean to the west and, loosely, by the Rocky Mountains to the east. Though ...
of North America, and the
Canada yew
''Taxus canadensis'', the Canada yew or Canadian yew, is a conifer native to central and eastern North America, thriving in swampy woods, ravines, riverbanks and on lake shores. Locally called simply "yew", this species is also referred to as ...
(''Taxus canadensis'') of Eastern and Central North America were the initial sources of
paclitaxel
Paclitaxel (PTX), sold under the brand name Taxol among others, is a chemotherapy medication used to treat a number of types of cancer. This includes ovarian cancer, esophageal cancer, breast cancer, lung cancer, Kaposi's sarcoma, cervical cancer ...
or
Taxol
Paclitaxel (PTX), sold under the brand name Taxol among others, is a chemotherapy medication used to treat a number of types of cancer. This includes ovarian cancer, esophageal cancer, breast cancer, lung cancer, Kaposi's sarcoma, cervical cance ...
, a
chemotherapeutic
Chemotherapy (often abbreviated to chemo and sometimes CTX or CTx) is a type of cancer treatment that uses one or more anti-cancer drugs (chemotherapeutic agents or alkylating agents) as part of a standardized chemotherapy regimen. Chemotherap ...
drug used in
breast
The breast is one of two prominences located on the upper ventral region of a primate's torso. Both females and males develop breasts from the same embryological tissues.
In females, it serves as the mammary gland, which produces and secret ...
and
lung cancer
Lung cancer, also known as lung carcinoma (since about 98–99% of all lung cancers are carcinomas), is a malignant lung tumor characterized by uncontrolled cell growth in tissue (biology), tissues of the lung. Lung carcinomas derive from tran ...
treatment and, more recently, in the production of the Taxus
drug eluting stent
A drug-eluting stent (DES) is a peripheral or coronary stent (a scaffold) placed into narrowed, diseased peripheral or coronary arteries that slowly release a drug to block cell proliferation. This prevents fibrosis that, together with clots ( ...
by
Boston Scientific
Boston Scientific Corporation ("BSC"), incorporated in Delaware, is a biomedical/biotechnology engineering firm and multinational manufacturer of medical devices used in interventional medical specialties, including interventional radiology, in ...
.
Over-harvesting
Overexploitation, also called overharvesting, refers to harvesting a renewable resource to the point of diminishing returns. Continued overexploitation can lead to the destruction of the resource, as it will be unable to replenish. The term app ...
of the Pacific yew for paclitaxel led to fears that it would become an
endangered species
An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inv ...
, since the drug was initially extracted from the bark of the yew, the harvesting of which kills the tree.
On January 18, 2008, the
Botanic Gardens Conservation International
Botanic Gardens Conservation International (BGCI) is a plant conservation biology, conservation Charitable organization, charity based in Kew, Surrey, England. It is a membership organisation, working with 800 botanic gardens in 118 countries, who ...
(representing
botanic gardens
A botanical garden or botanic gardenThe terms ''botanic'' and ''botanical'' and ''garden'' or ''gardens'' are used more-or-less interchangeably, although the word ''botanic'' is generally reserved for the earlier, more traditional gardens, an ...
in 120 countries) stated that "400 medicinal plants are at risk of extinction, from over-collection and deforestation, threatening the discovery of future cures for disease." These included yew trees, whose bark is used for the cancer drug
paclitaxel
Paclitaxel (PTX), sold under the brand name Taxol among others, is a chemotherapy medication used to treat a number of types of cancer. This includes ovarian cancer, esophageal cancer, breast cancer, lung cancer, Kaposi's sarcoma, cervical cancer ...
.
However, methods were developed to produce the drug semi-synthetically from the leaves of cultivated European yews. Those can be sustainably harvested without the need to further endanger wild populations, and the Pacific yew is no longer at risk. The more common Canada yew is also being successfully harvested in northern
Ontario
Ontario ( ; ) is one of the thirteen provinces and territories of Canada.Ontario is located in the geographic eastern half of Canada, but it has historically and politically been considered to be part of Central Canada. Located in Central Ca ...
,
Quebec
Quebec ( ; )According to the Canadian government, ''Québec'' (with the acute accent) is the official name in Canadian French and ''Quebec'' (without the accent) is the province's official name in Canadian English is one of the thirtee ...
and
New Brunswick
New Brunswick (french: Nouveau-Brunswick, , locally ) is one of the thirteen provinces and territories of Canada. It is one of the three Maritime provinces and one of the four Atlantic provinces. It is the only province with both English and ...
, and has become another major source of paclitaxel. Other yew species contain similar compounds with similar biochemical activity.
Docetaxel
Docetaxel (DTX or DXL), sold under the brand name Taxotere among others, is a chemotherapy medication used to treat a number of types of cancer. This includes breast cancer, head and neck cancer, stomach cancer, prostate cancer and non-small-ce ...
, an analogue of paclitaxel, is derived from the European yew (''Taxus baccata'').
In culture
The yew tree is a frequent symbol in the Christian poetry of
T. S. Eliot, especially his ''
Four Quartets
''Four Quartets'' is a set of four poems written by T. S. Eliot that were published over a six-year period. The first poem, ''Burnt Norton'', was published with a collection of his early works (1936's ''Collected Poems 1909–1935''). After a f ...
''.
Species and hybrids
*''
Taxus baccata
''Taxus baccata'' is a species of evergreen tree in the family Taxaceae, native to western, central and southern Europe (including Britain and Ireland), northwest Africa, northern Iran, and southwest Asia.Rushforth, K. (1999). ''Trees of Britain ...
'' , European yew
*''
Taxus brevifolia
''Taxus brevifolia'', the Pacific yew or western yew, is a species of tree in the yew family Taxaceae native to the Pacific Northwest of North America. It is a small evergreen conifer, thriving in moisture and otherwise tending to take the form o ...
'' , Pacific yew, western yew
*''
Taxus calcicola'' , Asian limestone yew
*''
Taxus canadensis
''Taxus canadensis'', the Canada yew or Canadian yew, is a conifer native to central and eastern North America, thriving in swampy woods, ravines, riverbanks and on lake shores. Locally called simply "yew", this species is also referred to as Am ...
'' , Canada yew
*''
Taxus chinensis
''Taxus chinensis'' is a species of yew. It is commonly called the Chinese yew, though this term also refers to '' Taxus celebica'' or ''Taxus sumatrana''.
This plant is used to produce medicines for cancer treatment, including Paclitaxel and ...
'' , China yew
*''
Taxus contorta'' , West Himalayan yew
*''
Taxus cuspidata
''Taxus cuspidata'', the Japanese yew or spreading yew, is a member of the genus ''Taxus'', native to Japan, Korea, northeast China and the extreme southeast of Russia.
It is an evergreen tree or large shrub growing to 10–18 m tall, with a tr ...
'' , Rigid branch yew, Japanese yew
*''
Taxus floridana
''Taxus floridana'', the Florida yew, is a species of yew, endemic to a small area of under 10 km² on the eastern side of the Apalachicola River in mesophytic forests of northern Florida at altitudes of 15–40 m. It is listed as critical ...
'' , Florida yew
*''
Taxus florinii'' , Florin yew
*''
Taxus globosa
''Taxus globosa'', the Mexican yew, is an evergreen shrub and one of the eight species of yew. The Mexican yew is a rare species, only known to be found in a small number of locations in eastern Mexico
Mexico (Spanish: México), officia ...
'' , Mesoamerican yew
*''
Taxus mairei'' , Maire yew
*''
Taxus wallichiana
''Taxus wallichiana'', the Himalayan yew, is a species of yew, native to the Himalaya and parts of south-east Asia. The species has a variety of uses in traditional medicine. It is currently classified as endangered by the IUCN.
Distribution an ...
'' , Wallich yew, East Himalayan yew
Fossil (extinct) species
*''
Taxus engelhardtii
''Taxus'' is a genus of coniferous trees or shrubs known as yews in the family Taxaceae. They are relatively slow-growing and can be very long-lived, and reach heights of , with trunk girth averaging . They have reddish bark, lanceolate, flat, d ...
'' – Oligocene, Bohemia, twig-leaves, similar to ''T. mairei''
[Kvaček, Z. 1984. Tertiary taxads of NW Bohemia. 1982 Acta Univ. Carol., Geol., Pokorny 4: 471–491.][ 203–289. ''T. brevifolia'' and ''T. globosa'' var. ''floridana'' thought to evolve from ancestral ''T. globosa'' by loss of stomata and papillae; ''T. canadensis'' recognized in Europe based on leaf fossils from late Tertiary deposits]
*''
Taxus inopinata'' – Upper Miocene, leaf, similar to ''T. baccata''
*''
Taxus masonii
''Taxus masonii'' is an extinct species of conifer in the yew family, Taxaceae, solely known from the middle Eocene sediments exposed in north central Oregon. The species was first described from a series of isolated fossil seeds in chert.
His ...
'' – Eocene
Clarno Formation Clarno may refer to:
Locations
* Clarno, Oregon
* Clarno, Wisconsin
** Clarno (community), Wisconsin
*Clarno Township, Lake County, South Dakota
Lake County is a county in the U.S. state of South Dakota. As of the 2020 United States Census, t ...
; Oregon, USA
*''
Taxus schornii'' – Miocene, northern Idaho
Commonly reported hybrids
*''
Taxus × media
''Taxus ''×'' media'', sometimes known simply as ''Taxus media'', is a conifer (more specifically, a yew) created by the hybridization of English yew ''Taxus baccata'' and Japanese yew ''Taxus cuspidata''. This hybridization is thought to have ...
''=''Taxus baccata'' × ''Taxus cuspidata''
*''
Taxus × hunnewelliana''=''Taxus cuspidata'' × ''Taxus canadensis''
References
External links
{{Taxonbar, from=Q27355
Conifer genera
Dioecious plants