Distribution. Valley of the Saskatchewan northwestward to the valley of the Yukon, growing sparingly near the banks of streams in forests of coniferous trees and in large numbers on sunny slopes and hillsides; the common Birch-tree of the Yukon basin. × _Betula commixta_ Sarg., a shrub, growing on the tundra near Dawson, Yukon Territory, is believed to be a hybrid between _B. alaskana_ and _B. glandulosa_ Michx. 8. Betula fontinalis Sarg. Black Birch. [Illustration: Fig. 206] Leaves ovate, acute or acuminate, sharply and often doubly serrate, except at the rounded or abruptly cuneate often unequal base, and sometimes slightly laciniately lobed, pale green, pilose above, and covered by conspicuous resinous glands when they unfold, at maturity thin and firm, dark dull green above, pale yellow-green, rather lustrous and covered by minute glandular dots below, 1′—2′ long, ¾′—1′ wide, with a slender pale midrib, remote glandular veins, and rather conspicuous reticulate veinlets; turning dull yellow in the autumn; petioles stout, puberulous, light yellow, glandular-dotted, flattened on the upper side, often flushed with red, ⅓′—½′ long; stipules broadly ovate, acute or rounded at apex, slightly ciliate, bright green, soon becoming pale and scarious. Flowers: staminate aments clustered, ½′—¾′ long and 1/16′ thick during the winter, with ovate acute light chestnut-brown scales pale and slightly ciliate on the margins, becoming 2′—2½′ long, and about ⅛′ thick, with apiculate scales; pistillate aments short-stalked, about ¾′ long, with ovate acute green scales; styles bright red. Fruit: strobiles cylindric, rather obtuse, puberulous or nearly glabrous, 1′—1¼′ long, ½′ thick, erect or pendulous on slender glandular peduncles, ¼′ to nearly ¾′ in length; their scales ciliate, puberulous, the lateral lobes ascending, shorter than the middle lobe; nut ovoid or obovoid, puberulous at apex, nearly as wide as its wing. A tree 20°—25° high with a short trunk, rarely more than 12′ or 14′ in diameter, ascending spreading and somewhat pendulous branches forming a broad open head, and slender branchlets, when they first appear light green glabrous or puberulous and covered with lustrous resinous glands persistent during their second season, and dark red-brown in their first winter; more commonly shrubby, with many thin spreading stems forming open clusters, 15°—20° high; often much lower, and frequently crowded in almost impenetrable thickets. Winter-buds ovoid, acute, very resinous, chestnut-brown, ¼′ long. Bark about ¼′ thick, dark bronze color, very lustrous, marked by pale brown longitudinal lenticels becoming on old trunks often 6′—8′ long and ¼′ wide. Wood soft and strong, light brown, with thick lighter-colored sapwood; sometimes used for fuel and fencing.