Bark grayish, tight, marked with distinct diamond-shaped ridges and furrows. Branches stout, drooping to spreading and ascending. Twigs 10 to 12 mm in diameter, conspicuous leaf scars. Buds (terminal) 10 to 15 mm long, 5 to 8 mm in diameter, scales imbricate. Leaves alternate, deciduous, odd-pinnately compound, 20 to 40 cm long with 5 to 7 drooping leaflets; yellow hairs and glandular hairs on lower leaflet surface, apex acuminate, margin finely serrate, base obtuse, on very short petiolules. Flowers unisexual, appearing in spring with developing leaves, staminate in 3-parted drooping catkins, pistillate terminal on new growth. Fruit subglobose to obovate, 3 to 5 cm in diameter, husk 1 cm thick, slow to open, shell of nut thick and hard, meat sweet.
Mockernut Hickory/Carya tomentosa
Pignut Hickory
Carya glabra (Mill.) Sweet
Bark light to dark gray, often blackish, rough and deeply furrowed. Branches stout, drooping to spreading. Twigs 3 to 5 mm in diameter, reddish brown, smooth. Buds ovoid, acute, glabrous, 8 to 12 mm long, scales imbricate. Leaves alternate, deciduous, odd-pinnately compound, 20 to 40 cm long, usually with 7 leaflets; upper pair and terminal largest, 10 to 15 cm long by 4 to 6 cm wide, broadly oval to slightly obovate. Flowers unisexual, staminate in 3-branched catkins appearing about the time of leaf maturity; pistillate terminal on new growth. Fruit oblong to obovoid to obpyriform, 30 mm in diameter by 35 mm long, husk about 3 mm thick, tardily dehiscent, shell of nut thick, meat sweet.
Pignut Hickory/Carya glabra
Shagbark Hickory
Carya ovata (Mill.) K. Koch
Bark smooth at first, then breaking into long, flat, irregular gray strips, to 5 mm thick, usually attached at the apex, free at the base. Branches stout, smooth, spreading to ascending. Twigs stout, orange-brown, leaf scars large. Buds (terminal), 10 to 20 mm long, 6 to 8 mm in diameter, scales imbricate. Leaves alternate, deciduous, odd-pinnately compound with 5 to 7 leaflets, usually 5 to 18 cm wide and 20 to 35 cm long; lateral leaflets ovate to ovate-lanceolate, terminal leaflet usually obovate, apices acute to acuminate, margins finely serrate, bases wedge-shaped, more or less yellow, pubescent below, gradually becoming glabrous with age. Flowers unisexual, appearing in spring with the developing leaves, staminate in 3-lobed catkins, pistillate on new growth. Fruits subglobose, 2.5 to 6 cm in diameter, husk 3 to 5 mm thick, shell of nut hard and moderately thin, meat sweet.