Betula is the classical name of the Birch-tree.
CONSPECTUS OF THE NORTH AMERICAN ARBORESCENT SPECIES.
Strobiles oblong-ovoid, nearly sessile, erect, the lateral lobes of their scales broad and slightly divergent; wing not broader than the nut; leaves with 9—11 pairs of veins; bark of young branches aromatic. Leaves heart-shaped or rounded at base; scales of the strobiles glabrous; bark dark brown, not separating into thin layers.1. [B. lenta] (A, C). Leaves cuneate or slightly heart-shaped at base; scales of the strobiles pubescent; bark yellow, or silvery white, rarely dull yellowish brown; separating into thin layers.2. [B. lutea] (A). Strobiles oblong or cylindric, erect, spreading or pendant, on slender peduncles; wing broader than the nut; leaves with 5—9 pairs of veins. Strobiles oblong, erect, ripening in May or June, their scales pubescent, deeply lobed, the lateral lobes erect; leaves rhombic-ovate, glaucescent and more or less silky-pubescent beneath; bark light reddish-brown, separating freely into thin persistent scales.3. [B. nigra] (A, C). Strobiles cylindric, pendant or spreading. Scales of the strobiles pubescent, with recurved lateral lobes, the middle lobe triangular, nearly as broad as long; leaves long-pointed; petioles slender, elongated. Leaves triangular to rhombic, bright green and lustrous; bark chalky white, not separable into thin layers.4. [B. populifolia] (A). Leaves ovate, cuneate to truncate or rounded at base, dull blue-green; bark white tinged with pink, lustrous, not easily separable into thin layers.5. [B. cœrulea] (A). Scales of the strobiles with ascending or spreading lateral lobes, the middle lobe usually acuminate, longer than broad; leaves acute or acuminate. Bark separating freely into thin layers; scales of the strobiles glabrous. Bark creamy white, or in some forms orange-brown; leaves ovate.6. [B. papyrifera] (A, B, C, F). Bark dull reddish brown or nearly white; leaves rhombic to deltoid-ovate.7. [B. alaskana] (A, B). Bark not separable into thin layers, dark brown; scales of the strobiles glabrous or puberulous; branchlets glandular. Leaves ovate, acute or acuminate, truncate or rounded at the broad base.8. [B. fontinalis] (B, F, G). Leaves broad-ovate to elliptic, acute, rounded or abruptly short-pointed, cuneate at base.9. [B. Eastwoodæ] (F).
1. [Betula lenta] L. Cherry Birch. Black Birch.
Leaves ovate to oblong-ovate, acute or acuminate, gradually narrowed and often unequal at the cordate or rounded base, sharply serrate with slender incurved teeth, or very rarely laciniately lobed (f. laciniata Rehdr.), when they unfold light green, coated on the lower surface with long white silky hairs, and slightly hairy on the upper surface, at maturity thin and membranaceous, dark dull green above, light yellow-green below, with small tufts of white hairs in the axils of the veins, 2½′—6′ long, 1½′—3′ wide, with a yellow midrib and primary veins prominent and hairy on the lower surface, and obscure reticulate cross veinlets; turning bright clear yellow late in the autumn; petioles stout, hairy, deeply grooved on the upper side, ¾′—1′ long; stipules ovate, acute, light green or nearly white, scarious and ciliate above the middle. Flowers: staminate aments during the winter about ¾′ long, nearly ¼′ thick, with ovate acute apiculate scales bright red-brown above the middle and light brown below it, becoming 3′—4′ long; pistillate aments ½′—¾′ long, about ⅛′ thick, with ovate pale green scales rounded at the apex; styles light pink. Fruit: strobiles oblong-ovoid, sessile, erect, glabrous, 1′—1½′ long, about ½′ thick; nut obovoid, pointed at base, rounded at apex, about as broad as its wing.
A tree, with aromatic bark and leaves, 70°—80° high, with a trunk 2°—5° in diameter, slender branches spreading almost at right angles, becoming pendulous toward the ends and gradually forming a narrow round-topped open graceful head, and branchlets light green, slightly viscid and pilose when they first appear, soon turning dark orange-brown, lustrous during the summer, bright red-brown in their first winter, becoming darker and finally dark dull brown slightly tinged with red. Winter-buds ovoid, acute, about ¼′ long, with ovate acute light chestnut-brown loosely imbricated scales, those of the inner ranks becoming ½′—¾′ long. Bark on young stems and branches close, smooth, lustrous, dark brown tinged with red, and marked by elongated horizontal pale lenticels, becoming on old trunks ½′—¾′ thick, dull, deeply furrowed and broken into large thick irregular plates covered with closely appressed scales. Wood heavy, very strong and hard, close-grained, dark brown tinged with red, with thin light brown or yellow sapwood of 70—80 layers of annual growth; largely used for floors, in the manufacture of furniture and for fuel, and occasionally in ship and boat-building. Sweet birch-oil distilled from the wood and bark is used for medicinal purposes and for flavoring as a substitute for oil of wintergreen, and beer is obtained by fermenting the sugary sap.
Distribution. Rich uplands from southern Maine to northwestern Vermont, and eastern Ohio and southward to northern Delaware and along the Appalachian Mountains up to altitudes of 4000° to northern Georgia; in Alabama, and in eastern Kentucky and Tennessee; a common forest tree at the north, and of its largest size on the western slopes of the southern Alleghany Mountains.
× Betula Jackii Schn., a natural hybrid of B. lenta with B. pumila Michx., has appeared in the Arnold Arboretum.