Hickory, a nut-bearing tree of the same family as the walnuts. Eighteen species are native to North America, and two to China. Most species are tall, ranging from 50 to 120 feet (15 to 37 m).
The gray or light-brown bark is usually deeply furrowed. The compound leaves consist of 5 to 17 tooth-edged, lance-shaped leaflets. A hickory tree has both male and female flowers. Male flowers are drooping catkins about six inches (15 cm) long. Female flowers are small and grow in clusters of two to five. Although the fruit is referred to as a nut, botanically it is a drupe rather than a nut. In most species, it has a thick, hard shell.
The pecan is a hickory but differs from other hickories in that its nuts are thin-shelled. The shagbark produces most of the hickory nuts that are marketed. It has grayish bark that loosens from the trunk in long strips. The tree grows to a height of 90 feet (27 m) and is found from the Atlantic coast west to Kansas. The shellbark, or king nut, is 70 to 100 feet (21 to 30 m) tall and is found in the northeastern United States. Its nuts are white or yellowish and have thick shells. The mockernut is slightly smaller and bears light-brown nuts with very thick shells. The pignut produces nuts that taste good when young but are bitter when mature. It has been extensively planted as an ornamental tree in parks of the eastern United States.
The shagbark, shellbark, mockernut, and pignut furnish valuable timber. The wood is tough, hard, and heavy. It is often used for tool handles, implements, and furniture and as fuel for smoking meats.
Hickories compose the genus Carya of the family Juglandaceae. The pecan is C. illinoensis, or C. pecan; shagbark, C. ovata; shellbark, C. laciniosa; mockernut, C. tomentosa; pignut, C. glabra. The Chinese hickories are the Cathay hickory, C. cathayensis, and the Tonkin, C. tonkinensis.