''Taxus wallichiana'', the Himalayan yew, is a species of

yew Yew is a common name given to various species of trees. It is most prominently given to any of various coniferous trees and shrubs in the genus ''Taxus'': * European yew or common yew (''Taxus baccata'') * Pacific yew or western yew (''Taxus br ...

, 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 The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...

Distribution and habitat

The species favours a reasonably wide range of habitats, growing in montane, temperate, warm temperate, and tropical submontane to high montane forests which may be deciduous, evergreen, or of mixed character. In forests, it tends to present as a low canopy tree; in open situations it usually forms a large, broadly spreading shrub. Elevation ranges from 900 m to 3,700 m.

Growth

It is a medium-sized evergreen

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 growing to 10 m tall, similar to '' Taxus baccata'' and sometimes treated as a

subspecies In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...

of it. The shoots are green at first, becoming brown after three or four years. The

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 ...

are thin, flat, slightly

falcate The following is a list of terms which are used to describe leaf morphology in the description and taxonomy of plants. Leaves may be simple (a single leaf blade or lamina) or compound (with several leaflets). The edge of the leaf may be regular ...

( sickle-shaped), 1.5–2.7 cm long and 2 mm broad, with a softly mucronate apex; they are arranged spirally on the shoots but twisted at the base to appear in two horizontal ranks on all except for erect lead shoots. It is

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 ...

, with the male and female cones on separate plants; the seed cone is highly modified,

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, with a single scale developing into a soft, juicy red

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 ...

1 cm diameter, containing a single dark brown seed 7 mm long. The

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 ...

cones are globose, 4 mm diameter, produced on the undersides of the shoots in early spring.

Species

Similar plants occurring further east through China to Taiwan, Vietnam and the Philippines are included in ''Taxus wallichiana'' as ''T. wallichiana'' var. ''chinensis'' (Pilger) Florin by some authors, but are more often treated as a separate species '' Taxus chinensis''.Rushforth, K. (1987). ''Conifers''. Helm .Farjon, A. (1998). ''World Checklist and Bibliography of Conifers''. Royal Botanic Gardens, Kew .

Medicinal uses

The tree has medicinal use in Ayurveda and Tibetan medicine. ''Taxus wallichiana'' is also a source of the chemical precursors to the anticancer drug paclitaxel (taxol). ''Taxus wallichiana'' is used for making tea by the Bhotiya tribal community in the Garhwal Himalaya. The stem bark of this species, which is locally known as ''thuner'', is collected for this purpose. This species is also used as fuelwood by the local communities. In Himachal it is known to be medicine for some types of cancer.

Conservation

The Himalayan yew has been subject to heavy exploitation for its leaves and bark across most of its range through the Himalayas and western China. Declines have been particularly heavy in India and Nepal, with losses of up to 90% having been reported. The degree of exploitation in other locations in its range is less well known, but is also assumed to be serious. The species is currently classified as endangered by the

. It is present in several protected areas, and at least some conservation and propagation measures are underway, with an eye to its commercial value in the medicine trade.

References

{{Taxonbar, from=Q186553 wallichiana Trees of Afghanistan Flora of tropical Asia Medicinal plants Plants used in traditional Chinese medicine Plants used in Ayurveda