South to Florida, ascending 3500 feet in Virginia; west to Minnesota, Nebraska, Kansas, Indian territory, and Texas. =Habit.=--A tall, slender tree, 50-75 feet high and 1 foot-2-1/2 feet in diameter at the ground, reaching greater dimensions southward. The trunk, tapering gradually to the point of branching, develops a capacious, spreading head, usually widest near the top, with lively green, finely cut foliage of great beauty, turning to a rich orange in autumn. Easily recognized in winter by its flat, yellowish buds. =Bark.=--Bark of trunk gray, close, smooth, rarely flaking off in thin plates; branches and branchlets smooth; leaf-scars prominent; season's shoots yellow, smooth, yellow-dotted. =Winter Buds and Leaves.=--Terminal buds long, yellow, flattish, often scythe-shaped, pointed, with a granulated surface; lateral buds much smaller, often ovate or rounded, pointed. Leaves pinnately compound, alternate, 12-15 inches long; rachis somewhat enlarged at base; stipules none; leaflets 5-11, opposite, 5-6 inches long, 1-2 inches wide, bright green and smooth above, paler and smooth or somewhat downy beneath, turning to orange yellow in autumn; outline lanceolate, or narrowly oval to oblong-obovate, serrate; apex taper-pointed to scarcely acute; base obtuse or rounded except that of the terminal leaflet, which is acute; sessile and inequilateral, except in terminal leaflet, which has a short stem and is equal-sided; sometimes scarcely distinguishable from the leaves of _C. porcina_; often decreasing regularly in size from the upper to the lower pair. =Inflorescence.=--May. Sterile and fertile flowers on the same tree, appearing when the leaves are fully grown,--sterile at the base of the season's shoots, or sometimes from the lateral buds of the preceding season, in slender, pendulous catkins, 3-4 inches long, usually in threes, branching umbel-like from a common peduncle; scale 3-lobed, hairy-glandular, middle lobe about the same length as the other two but narrower, considerably longer toward the end of the catkin; stamens mostly 5, anthers bearded at the tip: fertile flowers on peduncles at the end of the season's shoots; calyx 4-lobed, pubescent, adherent to the ovary; corolla none; stigmas 2. =Fruit.=--October. Single or in twos or threes at the ends of the branchlets, abundant, usually rather small, about 1 inch long, the width greater than the length; occasionally larger and somewhat pear-shaped: husk separating about to the middle into four segments, with sutures prominently winged at the top or almost to the base, or nearly wingless: nut usually thin-shelled: kernel white, sweetish at first, at length bitter.