Pignut hickory: C. glabro (Mill.) Sweet
Small pignut (False shagbark): C. ovalis (Wangh.) Sarg.
Shellbark (Shagbark hickory): C. laciniosa (Michx. f.) Loud.
Mockernut (Bigbud hickory): C. tomentosa (Poir.) Nutt.
Nutmeg hickory: C. myristicaeformis (Michx. f.) Nutt.
Source: Magness et al. 1971
The above species are all native to parts of the U.S. and produce nuts with edible kernels. They are not grown commercially for the nuts, but some quantities are harvested from native or ornamental trees. The trees become large, up to 100 feet or more, with compound, pinnate leaves. Fruits are generally near globose, glabrous, and somewhat ridged, and 1 to 1.5 inches long. The nut is encased in a fleshy husk which becomes fibrous and opens as the nuts mature. The shells are hard and woody. The kernels do not separate from the shells readily. Limited quantities either in shell or as kernels are marketed.