(Karya, Greek name for the walnut tree). Syn., Hicoria. Juglandaceae. Hickory. Trees grown for their handsome foliage and strong habit, and some species for their edible nuts.

Deciduous: branches with solid pith: leaves alternate, without stipules, with 3-17 serrate leaflets: flowers monoecious, apetalous, appearing with the leaves; staminate flowers in axillary, slender, pendulous catkins, each flower with 3-10 stamens, borne in the axil of a 3-lobed bract; pistillate flowers in a terminal, 2-10-flowered cluster or spike, consisting of a 1-celled ovary inclosed by a 4-lobed involucre: fruit globular to oblong, with a husk separating into 4 valves and a bony nut, incompletely 2-4-celled. - About 18 species of hickory, all in E. N. Amer. from Canada to Mex.; the Chinese species recently described by Dode from nuts only is probably not a Carya. See Rep. Mo. Bot. Gard. 7, pp. 28-42, pls. 1-23, and Rep. of U. S. Dept. Agric, Div. Pomol., Nut-Culture (1896), cited below as U. S. N. C. (the first number referring to the plate, the second and third to the figure). By some, Hicoria is considered to have priority, but Carya is retained as one of the "nomina conservanda" of the Vienna code of nomenclature, because of its long-established usage.

The hickories are hardy ornamental, usually tall trees with rather large, deciduous odd-pinnate leaves, small greenish flowers, the staminate ones in conspicuous pendulous racemes, and with rather large green dehiscent fruits inclosing a mostly edible nut. The hickories are among the most beautiful and most useful trees of the American forest, and are all very ornamental park trees, with a straight, sometimes high and slender trunk and a large, graceful, pyramidal or oblong head of usually fight green foliage, turning from yellow to orange or orange-brown in fall. They are hardy North except C. Pecan, C. aquatica and C. myristicaeformis, but C. Pecan thrives "rarely in Massachusetts in sheltered positions. Most of the species have heavy hard strong and tough wood, much valued for many purposes, especially for handles of tools, manufacture of carriages and wagons, also for making baskets and for fuel. The nuts of some species, as C. Pecan and C. ovata, also C. laciniosa and some varieties of C. glabra and C. alba, are edible, and are sold in large quantities, mostly gathered from the woods, though in later years orchards of improved varieties have been planted.

A large number of insects prey upon the hickory, attacking the wood, foliage and fruit, for which see the Fifth Ann. Rep. of the U. S. Entom. Com., pp. 285-329. There are also some fungi sometimes causing an early defoliation of the trees.

The hickories generally thrive best in rich moist soil, but some, especially C. glabra, C. alba and C. ovata, grow equally well in drier localities. They are of rather slow growth, and difficult to transplant if taken from the woods; therefore the seeds are often planted where the trees are to stand, but if grown in the nursery and transplanted several times when young, trees 6-10 ft. high may be transplanted successfully.

Propagation is usually by seeds stratified and sown in spring in rows about 3 inches deep; named varieties may be grafted in.spring in the greenhouse, on potted stock of C. cordiformis, which seems to be the best species for this purpose, veneer- or splice-grafting being usually employed; sometimes also increased by root-sprouts. For further horticultural advice, see Hickory-nut and Pecan.

A. Scales of buds valvate, 4+-6: fruit with winged sutures; nut usually thin-shelled: Ifts. 7-15, usually falcate.

B. Nut mostly elongated, almost terete; husk thin, splitting to the base; kernel sweet; cotyledons entire or only notched at the apex.

1. Pecan, Engler & Graebn

(Juglans Pecan, Marsh. Hicdria Pecan, Brit. C. illinoensis, Koch. C.olivseformis, Nutt.). Pecan. Fig. 823. To 170 ft., with branches pubescent when young: bark deeply furrowed, grayish brown: winter-buds yellow: leaflets 11-17, short-stalked, oblong-lanceolate, acuminate, serrate or doubly serrate, tomentose and glandular when young, usually glabrous at length, 4-7 in. long: staminate catkins almost sessile: fruit 3-10 in clusters or spikes, oblong, 1 1/2-3 1/2 in- long; nut ovoid or oblong, smooth, brown, irregularly marked with dark brown, 2-celled at the base; kernel sweet. From Iowa and Ind. south to Ala. and Texas; also in Mex. S.S. 7:338-9. A.G. 12:273-275. U.S.N.C.l, 8, 9. - This species is the most important as a fruit tree, and many named varieties are cultivated in the southern states, but it is tender N. The wood is less valuable than that of the other species. Hybrids are known of this species with C. cordiformis, C. alba and C. laciniosa, for which see Rep. Mo. Bot. Gard. 7, pls. 20-23 and Gng. 2:226. See Pecan.

Foliage and pistillate flowers of Carya Pecan.

Fig. 823. Foliage and pistillate flowers of Carya Pecan.

2. Myristicaeformis, Nutt. (Hicoria Myristicaeformis, Brit.)

Nutmeg Hickory. Tree, to 100 ft., with dark brown bark, broken into appressed scales: winter-buds brown: leaflets 5-11, short-stalked or almost sessile, ovate-lanceolate, the uppermost much larger and obovate, serrate, scurfy-pubescent beneath when young and with brown scales above, at length dark green above, silvery and lustrous beneath, 3-5 in. long: staminate catkins peduncled: fruit generally solitary, short-ovoid or obovate, about 11/2 in. long; nut ovoid, reddish brown marked with irregular spots and stripes, thick-shelled, 4-celled below; kernel sweet. From S. C. to Ark. and Mex. S.S. 7:342-3. - A very decorative species on account of its handsome foliage, but not hardy N.

bb. Nut usually so broad as long, compressed, with irregularly angled or reticulate surface, thin-shelled, 4-celled below; kernel bitter; cotyledons deeply 2-lobed.