4. Cárya microcárpa, Nutt. (Small Mockernut.) Leaflets about 5 (5 to 7), oblong-lanceolate, long-pointed, finely serrate, smooth, glandular beneath; buds small, ovate. Fruit small, subglobose, with a thin husk; nut not sharply angled, with a thin shell; edible. A large tree, 70 to 90 ft. high; New York, Pennsylvania, and westward.
C. porcìna.
5. Cárya porcìna, Nutt. (Pignut. Broom-hickory.) Leaflets 5 to 7 (usually 7), oblong-ovate, acuminate, serrate, smooth. Fruit pear-shaped to oval, somewhat rough, splitting regularly only about half-way. Nut large (1½ to 2 in. long), brownish, somewhat obcordate, with a thick, hard shell, and poor, bitter kernel. Tall tree, 70 to 80 ft. high, with dark-colored heart-wood, and rather smooth bark. Common on ridges.
C. amàra.
6. Cárya amàra, Nutt. (Bitternut. Swamp-hickory.) Leaflets 7 to 11, lanceolate to oblong-lanceolate, serrate with deep teeth. Fruit roundish-ovate, regularly separable only half-way, but friable at maturity. Nut small, white, subglobose, with a very thin shell and an extremely bitter kernel. Large tree with orange-yellow winter buds, and firm, not scaly, bark. Wild throughout, and sometimes cultivated.
C. olivæfórmis.
7. Cárya olivæfórmis, Nutt. (Pecan-nut.) Leaflets 13 to 15, ovate-lanceolate, serrate; lateral ones nearly sessile and decidedly curved. Fruit oblong, widest above the middle, with 4 distinct valves. Nut oblong, 1¼ in., nearer smooth than the other edible Hickory-nuts, the shell thin, but rather too hard to be broken by the fingers. The kernel is full, sweet, and good. A tall tree, 80 to 90 ft. high. Indiana and south; also cultivated, but not very successfully, as far north as New York City.