SALICACE^ 



163 



disk of the staminate flower broad, oblong; stamens numerous; disk of the pistillate 

 flower deep cup-shaped, nearly entire; ovary ovate, rounded at the apex, slightly 3 

 or 4-angled, short-stalked, nearly inclosed in the cup-shaped membranaceous disk. 

 Fruit on short stout pedicels, round-ovoid, buff color, slightly 3 or 4-lobed, deeply 

 pitted, thin-walled, about ^' long. 



A tree, sometimes 80 high, with a trunk 3-4 in diameter, gracefully spread- 

 ing and ascending branches forming a broad open head, and slender branchlets, pale 

 green and more or less pubescent or villose at first, soon becoming glabrous, and 

 light yellow-brown during their first season. Winter-buds narrow, acute, light 

 orange-brown, puberulous toward the base of the outer scales, the terminal about ^' 

 long, and two or three times as large as the much-compressed oblong lateral buds. 

 Bark pale gray or rarely white, and deeply divided into broad flat ridges. 



Distribution. Banks of mountain streams; southern Arizona and southwestern 

 New Mexico; widely distributed through northern Mexico. 



Often planted as a shade-tree in Mexican cities. 



**Leaf-stalks compressed laterally. 



9. Populus deltoidea. Marsh. Cottonvrood. 



Leaves deltoid or broadly ovate, acuminate, with entire points, or rarely rounded 

 at the apex, truncate, slightly cordate or occasionally abruptly wedge-shaped at the 

 entire base, coarsely crenately serrate above, with incurved glandular teeth, as they 



unfold gummy, fragrant with a balsamic odor, covered more thickly below than above 

 with soft white caducous hairs, and tomentose on the margins, at maturity thick and 

 firm, light bright green and lustrous, paler on the lower than on the upper surface, 

 3'-5' long and broad, with stout yellow midribs often tinged with red toward the base, 

 raised and rounded on the upper side, and conspicuous primary veins; their petioles 

 slender, pilose at first, soon glabrous, compressed laterally, yellow more or less 

 tinged with red, 2^-3^' long. Flowers: aments short-stalked, the staminate densely 

 flowered, 3'-4' long, ^' thick, with stout glabrous stems, the pistillate sparsely 

 flowered, thin-stemmed, often becoming a foot long before the fruit ripens, their 

 scales scarious, light brown, glabrous, dilated and irregularly divided at the apex 



