yew

yew, any tree or shrub of the genus Taxus (family Taxaceae), approximately eight species of ornamental evergreens, distributed throughout the Northern Hemisphere. Other trees called yew but not in this genus are the plum-yew, Prince Albert yew (see Podocarpaceae), and stinking yew. Two species are always shrubby, but the others may become trees up to 25 metres (about 80 feet) tall. Yews have rich, dark-green foliage. The branches are erect or spreading and are closely covered with flattened, linear leaves about ¹/₂ to 3 centimetres (about ¹/₅ to 1 ¹/₅ inches) long. The leaves have two yellowish- or grayish-green bands along the underside. They are attached in spirals around the branch but, because of a twist at their bases, appear to grow in two rows along the sides of the branch. The reproductive structures, small, rounded, scaly, and conelike on pollen-bearing plants and minute, green, and solitary on ovule-bearing plants, are located between the leafstalk and the stem. The seeds are usually solitary, borne at the ends of short branches. As a seed matures, it is enveloped by a fleshy, red, cup-shaped aril. The foliage and seeds, but not the arils, contain a poisonous alkaloid, sometimes fatal to livestock.

The many horticultural forms and cultivars of yews differ primarily in growth habit. Yew trees grow slowly but are long-lived and only moderately susceptible to attack by pests.

Yew wood is hard, fine-grained, and heavy, with white or creamy sapwood and amber to brown heartwood. The lumber was once popular for cabinetwork, implements, and archery bows; it is used more today for carved articles and turnery. The bark of some species, notably the Pacific yew (T. brevifolia), contains quantities of the alkaloid taxol, which has proved effective in the treatment of some types of cancer.

Aspects of the topic yew are discussed in the following places at Britannica.

Other

Articles from Britannica encyclopedias for elementary and high school students.

Yew - Children's Encyclopedia (Ages 8-11)

Yews are evergreen trees and bushes that grow in the northern half of the world. There are several species, or types, of yew. They include the English yew and the western yew.

yew - Student Encyclopedia (Ages 11 and up)

An ornamental evergreen, the yew is a very slow-growing and long-lived tree. The trunks of some English specimens are more than 10 feet (3 meters) in diameter and are estimated to be over 1,200 years old. The wood of the yew is highly valued for cabinetmaking because of its hardness and close grain.

Backyard Nature - The Yew

Fact Monster - Science - Yew

How Stuff Works - Science - Yew