
Juglandaceae (walnuts)
Hickories are trees in the genus Carya. There are 9 species that grow naturally in Missouri. All have alternate, feather-compound leaves with 5–13 unlobed leaflets per leaf. The largest leaflets are often near the leaf tip, though in some species they are uniform or have the middle leaflets larger. In nearly all our species, the leaflet margins are toothed. Hickory leaves typically turn golden yellow in the fall.
Male flowers and female flowers arise from different structures on the same tree. Male flowers occur on cylindrical drooping clusters (catkins). These are usually 3-branched with several catkins appearing at the base of the current season's growth. The female flowers are relatively few and inconspicuous, appearing near the tip of the new growth. They are fertilized when wind blows pollen to them from the male flowers. All our hickories bloom April–May.
Hickory fruits have the husk split lengthwise for at least half of the fruit length, releasing the nut. The nuts often have 4 lengthwise ridges; otherwise, the nut’s outer surface is hard (bony) and either smooth or shallowly wrinkled. All our hickories produce fruits September–October.
Twigs have the pith solid and homogeneous (not chambered).
Bark varies. Shagbark, shellbark, and water hickory have “shaggy” bark that peels away from the trunk in long, thin strips. The other species do not have shaggy bark.
Hickories are divided into two major groups: the pecan hickories and the true hickories:
Similar species: Hickories, black walnut, and butternut are in the same family, the Juglandaceae. Black walnut and butternut are types of walnuts (Juglans spp.). Walnuts have twigs with the pith chambered (hollow between cross-partitions) (not solid), and they usually have about 11–19 leaflets per leaf, with the leaflets typically uniform. Also, the fruit husk of walnuts does not split; instead, it remains fused to the deeply grooved or ridged nut.
Height: Pecan is the largest, reaching 130 feet. Shagbark, mockernut, bitternut, shellbark, and water hickory may reach 100 feet. The rest are, at most, medium-sized trees: pignut, 80 feet; black hickory, 70 feet; and sand hickory, 50 feet.
Oaks and hickories are the most numerous of the tree species in the state. But each species is distinct and each has its place in Missouri's forests. Hickories and oaks are very important members of Missouri's forests. About three-fourths of the trees you will find in our forests will be either an oak or a hickory.
Statewide. Different species have different distribution patterns.
Hickories and oaks are hardwoods, known for their strong, functional wood, which is manufactured into furniture, lumber, flooring, and other products. Yet the beauty, recreation, wildlife habitat, and water quality these forests provide are perhaps even more valuable.
While the wood of Missouri's white oak may be best suited for barrel staves, the wood of hickory trees seems destined to form the handles for many of our tools. Its more savory use, however, is cooking and smoking meats. The smell of barbecue on a warm summer evening is an unmistakable delight, and more often than not hickory wood provides the heat, smoke, and flavor.
Hickory is one of the most common woods in everyday use. It is heavy, hard, strong, and impact resistant. It is the preferred wood for striking-tool handles such as axes, picks, hammers, and hatchets. Early settlers used hickory in the hubs, rims, and spokes of wagon wheels. Besides its use in handles, better grades of hickory are used today in furniture and wall paneling.
Our 9 species of hickory are important parts of Missouri's oak-hickory woodlands and forests. We know that numerous species of hickory were also in the ancient forests of Europe, northern Africa, Asia, and North America before the Ice Age. Many hickory species have disappeared, and today there remain 17 species worldwide. There are two each in mainland China and Mexico. The other 15 are found in the central hardwood forest of the eastern and southern United States and Canada.
Hickory nuts are important food for many species of wildlife. Squirrels, turkeys, and ducks all feed on the nuts, which are often preferred over acorns.
There are no sharp dividing lines between trees, shrubs, and woody vines, or even between woody and nonwoody plants. “Wood” is a type of tissue made of cellulose and lignin that many plants develop as they mature — whether they are “woody” or not. Trees are woody plants over 13 feet tall with a single trunk. Shrubs are less than 13 feet tall, with multiple stems. Vines require support or else sprawl over the ground.