Carpinus is confined to the northern hemisphere, and is distributed from the Province of Quebec through the eastern United States to the highlands of Central America in the New World, and from Sweden to southern Europe, Asia Minor, the temperate Himalayas, Korea, southern China, Japan and Formosa in the Old World. Fifteen or sixteen species are recognized. Of the exotic species, the European and west Asian _Carpinus Betulus_ L. is frequently planted as an ornamental tree in the northeastern United States, where some of the species of eastern Asia promise to become valuable.
_Carpinus_ is the classical name of the Hornbeam.
1. Carpinus caroliniana Walt. Hornbeam. Blue Beech.
Leaves often somewhat falcate, long-pointed, sharply doubly serrate with stout spreading glandular teeth, except at the rounded or wedge-shaped often unequal base, pale bronze-green, and covered with long white hairs when they unfold, at maturity thin and firm, pale dull blue-green above, light yellow-green and glabrous or puberulous below, with small tufts of white hairs in the axils of the veins, 2′—4′ long, 1′—1¾′ wide, with a slender yellow midrib, numerous slender veins deeply impressed and conspicuous above, and prominent cross veinlets; turning deep scarlet and orange color late in the autumn; petioles slender, terete, hairy, about ⅓′ long, bright red while young; stipules ovate-lanceolate, acute, pubescent, hairy on the margins, bright red below, light yellow-green at the apex, ⅓′ long. Flowers: staminate aments 1½′ long when fully grown, with broadly ovate acute boat-shaped scales green below the middle, bright red above; pistillate aments ½′—¾′ long, with ovate acute hairy green scales; styles scarlet. Fruit: nut ⅓′ long, its involucre short-stalked, with one of the lateral lobes often wanting, coarsely serrate, but usually on one margin only of the middle lobe, 1′—1½′ long, nearly 1′ wide, crowded on slender terete pubescent red-brown stems 5′—6′ in length.
A bushy tree, rarely 40° high, with a short fluted trunk occasionally 2° in diameter, long slightly zigzag slender tough spreading branches pendulous toward the ends, and furnished with numerous short thin lateral branches growing at acute angles, and branchlets at first pale green coated with long white silky hairs, orange-brown and sometimes slightly pilose during the summer, becoming dark red and lustrous during their first winter and ultimately dull gray tinged with red. Winter-buds ovoid, acute, about ⅛′ long, with ovate acute chestnut-brown scales white and scarious on the margins. Bark light gray-brown, sometimes marked with broad dark brown horizontal bands, 1/16′—⅛′ thick. Wood light brown, with thick nearly white sapwood; sometimes used for levers, the handles of tools, and other small articles.