Leaves ovate, usually longer than broad, abruptly narrowed into a long slender entire acuminate point or rarely rounded at apex, truncate or slightly cordate at base, and coarsely crenately serrate, as they unfold slightly villose above and tomentose on the margins, soon glabrous, light green and very lustrous, 3′—3½′ long, 3½′—4′ wide, with a thin midrib, slender primary veins and reticulate veinlets occasionally furnished on the upper side at the insertion of the petiole with one or two small glands; petioles slender, compressed laterally, 2½′—3½′ long. Flowers: aments short-stalked, glabrous, the staminate 2′—2½′ in length, the pistillate becoming 4′—8′ long before the fruit ripens; scales fimbriately divided at apex, scarious, light brown; disk of the staminate flower broad, oblique, slightly thickened on the margins; stamens 20 or more, with short filaments and yellow anthers; disk of the pistillate flower cup-shaped, slightly lobed on the margin; ovary subglobose, with 3 or 4 sessile dilated or laciniately lobed stigmas. Fruit oblong-ovoid, gradually or abruptly narrowed to the blunt apex, thin-walled, about ⅖′ long and three or four times longer than the pedicel; seeds oblong-obovoid, rounded at apex, about 1/16′ in length. A tree 60°—90° tall with a trunk often 6° or 7° in diameter, erect and spreading branches forming a broad open head, and stout glabrous light yellow often angular branchlets conspicuously roughened by the elevated scars of fallen leaf-stalks. Winter-buds ovoid, acute, with light orange-brown puberulous scales. Bark pale, thick, divided by deep fissures into broad rounded ridges broken into closely appressed scales. Distribution. The common Cottonwood along the streams in the eastern foothill region of the Rocky Mountains from Saskatchewan to New Mexico, and ranging east to the Dakotas, western Nebraska, Kansas, Oklahoma and Texas. Often planted as a shade and street tree in the Rocky Mountain states; hardy in Massachusetts. 14. Populus balsamifera L. Cottonwood. _Populus angulata_ Michx. f. [Illustration: Fig. 130]