The Bitternut Hickory (Carya cordiformis) is a common hickory native to the eastern United States and southeast Canada, from Minnesota, southern Ontario and Vermont south to eastern Texas and northern Florida.
It is a large deciduous tree, growing up to 35 m tall (exceptionally to 47 m), with a trunk up to 1 m diameter. The leaves are 15-30 cm long, pinnate, with 7-11 leaflets, each leaflet lanceolate, 7-13 cm long, with the apical leaflets the largest but only slightly so. The flowers are small wind-pollinated catkins, produced in spring. The fruit is a very bitter nut, 2-3 cm long with a green four-valved cover which splits off at maturity in the fall, and a hard, bony shell. Another indentifying characteristic is its bright sulfur-yellow winter buds. No other hickory has this feature.
It is closely related to the Pecan, sharing similar leaf shape and being classified in the same section of the genus Carya sect. Apocarya, but unlike the Pecan, it does not have edible nuts. It is most readily distinguished from the Pecan by the smaller number of leaflets, with many leaves having only 7 leaflets (rarely fewer than 9, and often 11-13, in the Pecan). Hybrids with the Pecan are known, and named Carya × brownii.