Leaves 9′—12′ long, with slender villose pubescent petioles and rachis, and 15—19, usually 19, ovate-lanceolate to lanceolate long-pointed often slightly falcate leaflets, serrate with remote teeth except toward the usually rounded cuneate or rarely cordate base, thin, puberulous above while young, becoming bright green, lustrous and glabrous on the upper surface, below furnished with conspicuous tufts of pale hairs, and villose-pubescent along the midrib and primary veins, 2½′—4′ long and ¾′—1′ wide. Flowers: staminate in slender glabrous or sparingly villose aments 3′—5′ long; calyx elongated, coated like its bract with scurfy pubescence, divided into 5 or 6 acute lobes; stamens 30—40, with short connectives bifid at apex; ovary of the pistillate flower oblong-ovoid, thickly covered with villose pubescence, ⅛′ long, the border of the thin bract and bractlets much shorter than the calyx-lobes; stigma yellow. Fruit globose, 1¼′—2′ in diameter, with a thin dark-colored husk covered with short soft pubescence; nut nearly globose, somewhat flattened at the ends, faintly grooved with remote longitudinal depressions, thick shelled; seed small and sweet.
A tree usually 30°—40°, occasionally 75° high, with a tall trunk 1°—2° in diameter, stout pendulous branches forming a narrow round-topped head, and comparatively slender branchlets thickly coated when they first appear with villose pubescence, reddish brown and puberulous, and marked by pale lenticels and small elevated obscurely 3-lobed leaf scars during their first winter, becoming darker and nearly glabrous in their second year. Winter-buds coated with hoary tomentum; terminal acute, compressed, more or less enlarged at apex, ¼′—⅓′ long; axillary usually solitary, nearly globose, about 1/16′ in diameter. Bark gray-brown, smoothish, longitudinally fissured into narrow plates. Wood heavy, hard, rather coarse-grained, dark brown often mottled, with thick pale sapwood of from 8 to 10 layers of annual growth.
Distribution. Coast region of central California; banks of the lower Sacramento River; along streams near the western base of Mt. Diablo, and on eastern slope of the Napa Range near Atlas Peak east of Napa Valley; near Loyalton in the Sierra Valley.
Often cultivated in California as a shade tree and as stock on which to graft varieties of Juglans regia L., and rarely in the eastern states and in Europe. In California, a hybrid known as “Paradox” between J. Hindsii and J. regia has been artificially produced.
2. CARYA NUTT. Hickory.
Hicoria Rafn.
Trees, with smooth gray bark becoming on old trunks rough or scaly, strong hard tough brown heartwood, pale sapwood and tough terete flexible branchlets, solid pith, buds covered with few valvate or with numerous imbricated scales, the axillary buds much smaller than the terminal. Leaves often glandular-dotted, their petioles sometimes persistent on the branches during the winter, and in falling leaving large elevated oblong or semiorbicular more or less 3-lobed emarginate leaf-scars displaying small marginal clusters and central radiating lines of dark fibro-vascular bundle-scars; leaflets involute in the bud, ovate or obovate, usually acuminate, thick and firm, serrate, mostly unequal at base, with veins forked and running to the margins; turning clear bright yellow in the autumn. Aments of the staminate flowers ternate, slender, solitary or fascicled in the axils of leaves of the previous or rarely of the current year, or at the base of branches of the year from the inner scales of the terminal bud, the lateral branches in the axils of lanceolate acute persistent bracts; calyx usually 2 rarely 3-lobed, its bract free nearly to the base and usually much longer than the ovate rounded or acuminate calyx-lobes; stamens 3—10, in 2 or 3 series, their anthers ovate-oblong, emarginate or divided at apex, yellow or red, pilose or hirsute, as long or longer than their slender connectives; pistillate flowers sessile, in 2—10-flowered spikes, with a perianth-like involucre, slightly 4-ridged, unequally 4-lobed at apex, villose and covered on the outer surface with yellow scales more or less persistent on the fruit, the bract much longer than the bractlets and the single calyx-lobe; stigmas short, papillose-stigmatic. Fruit ovoid, globose or pyriform, with a thin or thick husk becoming hard and woody at maturity, 4-valved, the sutures alternate with those of the nut, sometimes more or less broadly winged, splitting to the base or to the middle; nut oblong, obovoid or subglobose, acute, acuminate, or rounded at apex, tipped by the hardened remnants of the style, narrowed and usually rounded at base, cylindric, or compressed contrary to the valves, the shell thin and brittle or thick, hard, and bony, smooth or variously rugose or ridged on the outer surface, 4-celled at base, 2-celled at apex. Seed compressed, variously grooved on the back of the flat or concave lobes, sweet or bitter.
Carya is confined to the temperate region of eastern North America from the valley of the St. Lawrence River to the highlands of Mexico, and to southern China where one species occurs. Of the seventeen species, fifteen inhabit the territory of the United States.
The generic name is from Καρύα, an ancient name of the Walnut.