Walnut, a tree valued for its edible nuts, for its beautiful wood, and as a shade tree. Although the fruit is called a nut, botanically it is a drupe, rather than a true nut. There are some 50 species of walnuts. Most prized are the English walnut and the black walnut.

The English walnut, also called the European and Persian walnut, is native to southeastern Europe and Asia. It is widely cultivated for its nuts. In the United States it is grown chiefly in California. Its soft shell is easy to split, and the meat can be removed in two pieces. The beautiful light-brown wood of the English walnut tree is known as Circassian walnut and French walnut. It is used for fine furniture and gunstocks. The tree grows to 90 feet (27 m) tall, with a trunk diameter of 4 feet (1.2 m). Its bark is smooth and whitish when young, gray and fissured when old. The leaves are made up of seven to nine leaflets growing on opposite sides of a central leafstalk.

The English walnutThe English walnut has a soft shell that is easily split, and the meat can be removed in two pieces.

The black walnut of eastern North America grows to a height of 100 feet (30 m), with a trunk diameter of 4 feet (1.2 m). Its feather-like leaves are made up of 7 to 21 leaflets. The purple-brown wood, the most expensive domestic wood in North America, is used chiefly for gunstocks and furniture, and as a veneer for cabinetmaking.

The black walnut is little cultivated. Both wood and nuts are obtained chiefly from wild trees. The nuts are particularly valued because they keep their flavor when cooked in candies and pastries. However, they are extremely hard and difficult to open, and the meats can be extracted only in pieces.

The butternut, or white walnut, of eastern North America grows to 100 feet (30 m) tall. The nuts are long, pointed, and thick-shelled, and the kernels are oily. The young nuts are pickled in their husks. In colonial days, brown household dye was made from the bark and the husks of the nuts. The wood is light and soft. It is used in cabinet-making and for furniture.

Walnuts belong to the family Juglandaceae. The English walnut is Juglans regia; the black, J. nigra; the butternut, J. cinerea.