Trees, with smooth close bark, hard strong close-grained wood, elongated conic buds covered by numerous imbricated scales, the inner lengthening after the opening of the buds. Leaves open and concave in the bud, ovate, acute, often cordate; stipules strap-shaped to oblong-obovate. Flowers: staminate in aments emerging in very early spring from buds produced the previous season near the ends of short lateral branchlets of the year and inclosed during the winter, composed of 3—20 stamens crowded on a pilose receptacle adnate to the base of a nearly sessile ovate acute coriaceous scale longer than the stamens; filaments short, slender, 2-branched, each branch bearing a 1-celled oblong yellow half-anther hairy at the apex; pistillate in lax semi-erect aments terminal on leafy branches of the year, in pairs at the base of an ovate acute leafy deciduous scale, each flower subtended by a small acute bract with two minute bractlets at its base; calyx adnate to the ovary and dentate on the free narrow border. Nut ovoid, acute, compressed, conspicuously longitudinally ribbed, bearing at the apex the remnants of the calyx, marked on the broad base by a large pale scar and separating at maturity in the autumn from the leaf-like 3-lobed conspicuously serrate green involucre formed by the enlargement of the bract and bractlets of the flower and inclosing only the base of the nut, fully grown at mid-summer and loosely imbricated into a long-stalked open cluster. (_Eucarpinus._) 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. [Illustration: Fig. 191]