AppearanceIt is a small- to medium-sized evergreen tree, growing 10–20 metres tall, with a trunk up to 2 metres in diameter. The bark is thin, scaly brown, coming off in small flakes aligned with the stem. The leaves are lanceolate, flat, dark green, 1–4 centimetres long and 2–3 millimetres 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, except on erect leading shoots where the spiral arrangement is more obvious. The leaves are highly poisonous.
The seed cones are highly modified, each cone containing a single seed 4–7 millimetres long partly surrounded by a modified scale which develops into a soft, bright red berry-like structure called an aril, 8–15 millimetres long and wide and open at the end. The arils are mature 6 to 9 months after pollination, and with the seed contained are eaten by thrushes, waxwings and other birds, which disperse the hard seeds undamaged in their droppings; maturation of the arils is spread over 2 to 3 months, increasing the chances of successful seed dispersal. The seeds themselves are extremely poisonous and bitter, but are opened and eaten by some bird species including Hawfinches Greenfinches and Great Tits. The aril is not poisonous, and is gelatinous and very sweet tasting. The male cones are globose, 3–6 millimetres diameter, and shed their pollen in early spring. It is mostly dioecious, but occasional individuals can be variably monoecious, or change sex with time.
NamingThe word ''yew'' is from Proto-Germanic ''*īwa-'', possibly originally a loanword from Gaulish ''*ivos'', compare Irish ''ēo'', Welsh ''ywen'', French ''if'' . ''Baccata'' is Latin for ''bearing red berries''. The word ''yew'' as it was originally used seems to refer to the color brown. The yew was known to Theophrastus, who noted its preference for mountain coolness and shade, its evergreen character and its slow growth.
Most romance languages kept a version of the Latin word ''taxus'' from the same root as ''toxic''. In Slavic languages, the same root is preserved: Russian ''tiss'' , Slovenian ''tisa'', Serbian ''tisa'' . In Albanian it is named ''tis''.
The common yew was one of the many species first described by Linnaeus. Along with around 30 other species, it is classified in the family Taxaceae, which is now firmly classified as a conifer in the order Pinales.
StatusClippings from ancient specimens in the UK, including the Fortingall Yew, were taken to the Royal Botanic Gardens in Edinburgh to form a mile-long hedge. The purpose of this "Yew Conservation Hedge Project" is to maintain the DNA of ''Taxus baccata''. The species is threatened by felling, partly due to rising demand from pharmaceutical companies, and disease.
DefenseMost parts of the tree are toxic, except the bright red aril surrounding the seed. The foliage remains toxic even when wilted, and toxicity increases in potency when dried. Ingestion and subsequent excretion by birds whose beaks and digestive systems do not break down the seed's coating are the primary means of yew dispersal. The major toxin within the yew is the alkaloid taxine. Horses have the lowest tolerance to taxine, with a lethal dose of 200–400 mg/kg body weight, cattle, pigs, and other livestock are only slightly less vulnerable. Symptoms of yew poisoning include an accelerated heart rate, muscle tremors, convulsions, collapse, difficulty breathing, circulation impairment and eventually heart failure. However, there may be no symptoms, and if poisoning remains undetected death may occur within hours. Fatal poisoning in humans is very rare, usually occurring after consuming yew foliage. The leaves are more toxic than the seed.
UsesOne of the world's oldest surviving wooden artifacts is a Clactonian yew spear head, found in 1911 at Clacton-on-sea, in Essex, UK. It is estimated to be about 450,000 years old.
In the ancient Celtic world, the yew tree had extraordinary importance; a passage by Caesar narrates that Catuvolcus, chief of the Eburones poisoned himself with yew rather than submit to Rome . Similarly, Florus notes that when the Cantabrians were under siege by the legate Gaius Furnius in 22 BC, most of them took their lives either by the sword or by fire or by a poison extracted ''ex arboribus taxeis'', that is, from the yew tree . In a similar way, Orosius notes that when the Astures were besieged at ''Mons Medullius'', they preferred to die by their own swords or by the yew tree poison rather than surrender .
CulturalToday European yew is widely used in landscaping and ornamental horticulture. Due to its dense, dark green, mature foliage, and its tolerance of even very severe pruning, it is used especially for formal hedges and topiary. Its relatively slow growth rate means that in such situations it needs to be clipped only once per year .
Well over 200 cultivars of ''T. baccata'' have been named. The most popular of these are the Irish yew , a fastigiate cultivar of the European yew selected from two trees found growing in Ireland, and the several cultivars with yellow leaves, collectively known as "golden yew". In some locations, e.g. when hemmed in by buildings or other trees, an Irish yew can reach 20 feet in height without exceeding 2 feet in diameter at its thickest point, although with age many Irish yews assume a fat cigar shape rather than being truly columnar.
European yew will tolerate growing in a wide range of soils and situations, including shallow chalk soils and shade, although in deep shade its foliage may be less dense. However it cannot tolerate waterlogging, and in poorly-draining situations is liable to succumb to the root-rotting pathogen ''Phytophthora cinnamomi''.
In Europe, ''Taxus baccata'' grows naturally north to Molde in southern Norway, but it is used in gardens further north. It is also popular as a bonsai in many parts of Europe and makes a handsome small to large sized bonsai.
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