Yew

Yew, common name for a genus of evergreen, needle-bearing trees and shrubs, and, loosely, for other members of the family to which the yews belong. Yews are native to temperate and subtropical climates throughout the world and are widely cultivated as ornamental plants, especially as hedges. The needle leaves are produced more or less in two ranks along the sides of the terminal branchlets. These leaves are dark green on the upper surface and yellower beneath; they persist through the winter. Flowers are inconspicuous; the fruit is an attractive scarlet berry. The wood is slow-growing, strong, and fine grained and is utilized in cabinetmaking and for archery bows. The branches are often twisted or gnarled; the bark is red and scaly. Principal ornamental species include the English yew and the hardier Japanese yew, both with several horticultural varieties. The ground hemlock, native North American yew of wooded hillsides and ravines, is a straggly shrub, rarely more than about 90 cm (about 36 in) tall. The Pacific, or western, yew is a tall tree found in old-growth forests from California to Alaska.

The foliage and seeds of yew contain highly poisonous alkaloids that act to stop the heart of an animal so suddenly that no symptoms are seen; the animal simply drops dead. The berries are attractive to children and their flesh is not distasteful. Fortunately, the flesh of the berries is the least poisonous part of the plant.

The drug paclitaxel (Taxol), approved in 1992 for treating ovarian and other cancers, is extracted from the bark of the Pacific yew. The tree is scarce, however, and large amounts of paclitaxel are needed for treatment. Scientists are studying the feasibility of cultivating the trees to harvest the drug from the bark, as well as the possibility of extracting the drug from the branches and needles. A partially synthetic form of the drug is also under development.

Scientific classification: Yews make up the genus Taxus of the family Taxaceae. The English yew is classified as Taxus baccata; the Japanese yew as Taxus cuspidata; the ground hemlock as Taxus canadensis; and the Pacific, or western, yew as Taxus brevifolia.