190 TREES OF NORTH AMERICA 



Scales of the pistillate ament persistent and forming a woody strobile ; nut without an in- 

 volucre, more or less broadly winged ; staminate flowers 3-6 together in the axils of the 

 scales of the ament ; calyx present ; pistillate flowers without a calyx. 



Pistillate aments solitary, their scales 3-lobed, becoming thin, brown, and woody, de- 

 ciduous ; stamens 2 ; filaments 2-branehed, each division bearing a half -anther ; 

 winter-buds covered by imbricated scales. 3. Betula. 



Pistillate aments racemose, their scales erose or 5-toothed, becoming thick, woody, and 

 dark-colored, persistent ; stamens 1-3 or 4 ; filaments simple ; wings of the nut often 

 reduced to a narrow border ; winter-buds without scales. 4. Alnus. 



1. CARFINTJS, L. Hornbeam. 



Trees, with smooth close bark, hard strong close-grained wood, elongated conical 

 buds covered by numerous imbricated scales, the inner lengthening after the open- 

 ing 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, and 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 semierect 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. Nuts ovate, 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 involucres formed by the enlargement of the bract and 

 bractlets of the flowers and inclosing only the base of the nuts, fully grown at mid- 

 summer and loosely imbricated into a long-stalked open cluster. 



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, central China and Japan in the Old World. Ten or twelve 

 species are recognized; one only is American. 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, l'-lf wide, with slender yellow midribs, numerous slender veins deeply 

 impressed and conspicuous above, and prominent cross veinlets, turning deep scarlet 

 and orange color late in the autumn; their petioles slender, terete, hairy, about ' 

 long, bright red while young; stipules ovate-lanceolate, acute, pubescent, hairy on the 



