Top 10 Most Dangerous Fruits and Vegetables in the World
Taxus is a genus of yews, small coniferous trees or shrubs in the yew family
Taxaceae. They are relatively slow-growing and can be very long-lived, and reach
heights of 1–40 m, with trunk diameters of up to 4 m. They have reddish bark,
lanceolate, flat, dark-green leaves 1–4 cm long and 2–3 mm 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.
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
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 (T. globosa, native to eastern Mexico south
to Honduras) 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.
All species of yew contain highly poisonous alkaloids known as taxanes, with
some variation in 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 taxanes 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 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 Willow Beauty.
Yew is an evergreen shrub with soft bright green needles similar to the
"Christmas tree." The berries are soft red capsules with a hard green stone in
the center. Eating more than three yew berries can cause vomiting, abdominal
pain, dizziness, difficulty in breathing, and changes in your child's heart
Taxus is possibly from the Greek ‘taxon’, ‘bow’ as a result of the use of its
wood to make bows. Persian has ‘tachš’ for ‘bow’. A mummy from the Chalcolithic
age, around 4000BC, was found with an unfinished bow made of yew so its use for
this purpose goes back much further than the English long bowmen usually
associated with it. Common Names and Synonyms are yew, Irish yew and English
All parts, except the flesh of the berries, contain taxin(e) a complex of
alkaloids which is rapidly absorbed. Also present are ephedrine, a cyanogenic
glycoside (taxiphyllin) and a volatile oil.
Where poisoning does occur, in animals or humans, there may be no symptoms and
death may follow within a few hours of ingestion. If symptoms do occur, they
include trembling, staggering, coldness, weak pulse and collapse.
Yew is one of the plants where the poison is not destroyed when the plant dies.
Thus, branches removed from a yew by high winds or pruning will retain their
Though the berries are harmless, the seed within is highly toxic. Unbroken it
will pass through the body without being digested but if the seed is chewed
poisoning can occur with as few as three berries.
Most incidents with yew relate to animals though it was eaten, in the 1980s, by
four prisoners as a means of suicide. Three of the four succeeded.
The interactive CD-ROM produced by St Thomas' and Kew Gardens cites a number of
case reports all involving ingestion of leaves or bark. In one case it is noted
that a nineteen month old child accidentally ingested some plant material.
Intact seeds were found in his stools confirming that these are not digested.
The child recovered.
Farmers have reported cases of poisoning in cattle when dead yew clippings have
been dumped on grazing land. The assumption is that someone clipped a yew hedge
in the garden, left the clippings to wither thinking that would render them safe
before 'recycling' them by dumping them on farmland.
A visitor to the Alnwick Garden Poison Garden talked about his elderly neighbour
who, being no longer able to manage it himself, had a group of young people in
to tidy up his garden. They trimmed his yews and threw the clippings over the
fence into the field at the bottom of the garden where three heifers died after
eating the cuttings.
Folklore and Facts
Some years ago, it was found that the taxol found in yew could be used to
produce chemotherapy treatments for breast and other cancers. The drug produced
in this way is called paclitaxel. (Until someone was kind enough to correct me,
I was one of the many people who thought tamoxifen was produced from yew. It is
not. Tamoxifen is a synthetic drug.) For some time, large gardens made a point
of keeping their yew prunings and passing these to companies to extract the
taxol and produce these drugs. This was an expensive process and produced only
limited amounts of the drug. Since then, however, it has been discovered that
taxol is produced from a fungus that lives in the yew. Other fungi have also
been found that are able to be used to produce paclitaxel. With some,
artificially brewing is possible and, once that process is scaled up, it should
reduce the cost and increase the availability of breast cancer treatments.
Though toxic to most animals, deer do graze on yew and gardeners are advised to
avoid growing yew if there is a possibility of deer getting into the garden
because it is a favourite food. That said, the list of plants which deer will
browse is a very long one and there are reports of poisoning incidents so it may
be large amounts are toxic to deer.
The idea that yew was grown in churchyards for making longbows is a myth. Bows
were made, primarily, from the trunk of the tree so the tree was destroyed. In
addition, yew grown in Britain is too brittle so the famous English longbow was
made from wood imported from Europe.
The roots of the yew are very fine and will grow through the eyes of the dead to
prevent them seeing their way back to the world of the living.
Yew is very long-lived and, in many cases, the yew tree in the churchyard
predates the church so, the church was built round a yew tree because the pagan
belief about the roots was so deep-seated.
Its longevity leads to its featuring in tales of reincarnation. If two yews are
intertwined it is believed that they grew after yew stakes were driven into the
chests of lovers whose relationship appalled their community.
Many place names have their origins in particular trees. York is a corruption of
an Anglo-Saxon word meaning ‘the place where yew grows’.
John Gerard quotes Galen and others as saying that the yew is very venomous
taken internally and that sleeping under a Yew can cause sickness and oftentimes
death. He then dismisses these stories by saying that ‘when I was young and went
to school, divers of my school fellows and likewise myself did eat our fills of
the berries of this tree and hath not only slept under the shadow thereof, but
among the branches also, without hurt at all, and that not one time, but many
Thomas Johnson resolves the difference of opinion between the foreign ancient
sources and Gerard by asserting that the yew in England is not poisonous but, in
other countries, it is highly venomous.
Dated 06 June 2013