62 SILVA OF NORTH AMERICA. BETULACES. 
pilose above, and are coated below, especially on the midribs and on the petioles, with thick white 
tomentum, and at maturity they are thin and very tough in texture, from an inch and a half to three 
inches long, from one to two inches broad, deep green and very lustrous on the upper surface, and pale 
yellow-green on the lower surface, which is pubescent until after the leaves are fully grown, and then 
gradually becomes glabrous, with the exception of a persistent clothing of pale hairs along the stout 
midribs and remote primary veins ; they are borne on slender slightly fattened tomentose petioles about 
half an inch long, and in the autumn turn a dull yellow before falling. The stipules are ovate, rounded 
or acute at the apex, pale green and covered on the lower surface with white hairs, and become reflexed 
and usually fall soon after the expansion of the leaf. During the winter the clustered staminate catkins 
are about seven eighths of an inch in length and one sixteenth of an inch in thickness, and are covered 
with ovate rounded dull chestnut-brown lustrous scales, and when they are fully grown and the flowers 
open in very early spring they are from two to three inches long and an eighth of an inch thick, with 
scales which are light yellow below the middle and bright chestnut-brown toward the apex. The 
pistillate catkins are about a third of an inch in length, with bright green ovate scales pubescent on the 
back and rounded or acute at the apex, which is ciliate with long white hairs, and are borne on slender 
tomentose peduncles bibracteolate with lanceolate acute hairy caducous bractlets, and about a quarter of 
an inch long. The strobiles ripen in May at the south and in the middle of June at the north ; they 
are cylindrical, from an inch to an inch and a half long and half an inch thick, and stand erect or 
nearly so on stout tomentose peduncles half an inch in length and conspicuously marked with the scars 
of the fallen bractlets; the scales are oblong-obovate and three-lobed by wide sinuses nearly to the 
middle, the lateral lobes being erect and slightly spreading and rather shorter than the central lobe; 
they are nearly a quarter of an inch in length, three or four times as long as they are broad, and 
pubescent on the back. The nut is broadly ovate or oval, about an eighth of an inch long, pubescent 
or puberulous at the apex, and furnished with a thin puberulous wing ciliate on the margin and as 
broad or a little broader than the seed. 
Betula nigra inhabits the banks of streams, ponds, and swamps, growing in deep rich soil which 
is often inundated for several weeks at a time. In Massachusetts it occurs on the banks of the 
Nashua River near Fitchburg,’ and is common on those of the Merrimac River in the neighborhood of 
Lawrence and Lowell, and on the Spicket and Shawsheen Rivers near their junction with the Merrimac.’ 
It reappears on the banks of Wading River on Long Island, New York, and then extends southward 
to western Florida through the regions east of the Alleghany Mountains with the exception of those 
in the immediate neighborhood of the coast; through the Gulf States it ranges to the valley of the 
Trinity River in Texas, and through the Mississippi Valley to the Indian Territory, eastern Kansas, 
the bottom-lands of the Missouri River in eastern Nebraska,‘ central Minnesota,®> and southern Wis- 
consin and Ohio. 
The wood of Betula nigra is light, rather hard, strong, and close-grained ; it is light brown, with pale 
sapwood composed of forty or fifty layers of annual growth, and contains numerous obscure medullary 
rays. The specific gravity of the absolutely dry wood is 0.5762, a cubic foot weighing 35.91 pounds. 
It is used in the manufacture of furniture, wooden-ware, wooden shoes, and ox-yokes, and in turnery. 
First described by Plukenet in 1696,° the River Birch was introduced into English plantations by 
Peter Collinson’ in 1736.° It is one of the most interesting trees of its genus. It is the only semi- 
1 In 1891 Mr. G. E. Stone of Worcester, Massachusetts, estab- Betula foliis ovatis oblongis acuminatis serratis, Clayton, Fl. Virgin. 
lished the fact of the existence of Betula nigra on the banks of the 188. 
Nashua River. Betula nigra foliis rhombeis ovatis acuminatis duplicato serratis, 
2 Robinson, Bull. Essex Inst. xi. 32. Romans, Nat. Hist. Florida, 28. 
* Mason, Eighth Bienn. Rep. State Board Agric. Kansas, 271. T See i. 8. 
4 Bessey, Rep. Nebraska State Board Agric. 1894, 111. 8 Aiton, Hort. Kew. iii. 336.— Loudon, Arb. Brit. iii. 1710, f. 
5 Maemillan, Metasperme of the Minnesota Valley, 189. 1562, 1563, t. 
6 Betula nigra Virginiana, Alm. Bot. 67 (excl. syn.). — Ray, Hist. 
Pl. iii. Dendr. 12. 
