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 covering; 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 cœrulea Blanch. Blue Birch. [Illustration: Fig. 198] 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′—2½′ long, 1′—1½′ wide; petioles slender, ¾′—1¼′ long, yellow more or less deeply tinged with red. Flowers: staminate aments usually in pairs, or singly or in 3’s, 1¼′—2′ long, about 3/16′ thick, with ovate rounded short-pointed scales; pistillate aments slender, about ⅓′ long, with acuminate pale green much reflexed scales. Fruit: strobiles cylindric, pubescent, slightly narrowed at the obtuse apex, about 1′ long and ¼′ thick, pendant on slender peduncles ¼′—½′ 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 bright red-brown; often forming clumps of several stems. Bark thin, white tinged with rose, lustrous, not readily separable into layers, the inner bark light orange color.