BETULACE.E 



insertion of the branches, becoming at the base of old trees thicker, nearly black, and 

 irregularly broken by shallow fissures. Wood light, soft, not strong, close-grained, not 

 durable, light brown, with thick nearly white sap wood; used in the manufacture of spools, 

 shoe-pegs and wood pulp, for the hoops of barrels, and largely for fuel. 



Distribution. Dry gravelly barren soil or on the margins of swamps and ponds; Prince 

 Edward Island, Nova Scotia, New Brunswick, and the valley of the lower St. Lawrence 

 River southward to northeastern, central and on South Mountain, Franklin County, 

 Pennsylvania, and northern Delaware, and westward through northern New England and 

 New York, ascending sometimes to altitudes of 1800, to the southern shores of Lake 

 Ontario, and at the foot of Lake Michigan, Indiana; rare and local in the interior, very 

 abundant in the coast region of New England and the middle states; springing up in great 

 numbers on abandoned farm-lands or on lands stripped by fire of their original forest cover- 

 ing; most valuable in its ability to grow rapidly in sterile soil and to afford protection to 

 the seedlings of more valuable and less rapid-growing trees. 



A form with deeply divided leaves (var. laciniata Loud.) and one with purple leaves 

 (var. purpurea E & B) are occasionally cultivated. 



A shrub believed to be a natural hybrid of B. populifolia with B. pumila Michx. has 

 been found near Mt. Mansfield, Vermont. 



5. Betula coerulea Blanch. Blue Birch. 



Leaves ovate, long-pointed, broadly or narrowly concave-cuneate at the entire often 

 unequal base, sharply mostly doubly serrate above with straight or incurved glandular 

 often apiculate teeth, covered above when they unfold with pale deciduous glands, at 

 maturity dull bluish green above, pale yellow-green below, and sparingly villose along the 

 under side of the slender yellow midrib and primary veins, 2'-2|' long, I'-lJ' wide: 



Fig. 198 



petioles slender, f'-lf long, yellow more or less deeply tinged with red. Flowers: stam- 

 inate aments usually in pairs, or singly or in 3's, l|'-2' long, about T y thick, with ovate 

 rounded short-pointed scales; pistillate aments slender, about f ' long, with acuminate pale 

 green much reflexed scales. Fruit: strobiles cylindric, pubescent, slightly narrowed at the 

 obtuse apex, about 1' long and \' thick, pendant on slender peduncles \'-\' in length; nut 

 ellipsoidal, much narrower than its broad wing. 



A tree, rarely more than 30 high, with a trunk 8' -10' in diameter, small ascending 

 finally spreading branches, and slender branchlets marked by numerous small raised pale 

 lenticels, purplish and sparingly villose when they first appear, soon glabrous, becoming 



