132 



TREES OF NORTH AMERICA 



maturity subcoriaceous, bright yellow-green, very lustrous, U'-2' long and broad, with a 

 slender yellow midrib and obscure primary veins; petioles laterally compressed, sparingly 

 villose when they first appear, soon glabrous, H'-2' long; leaves on vigorous leading shoots 

 often rounded at apex, cuneate at base, and often 2' long and 3' w r ide, with petioles often 

 3' in length. Flowers: stamina te aments dense, cylindric, l'-lf long, the pistillate 

 slender, many-flowered, l^'-2' long, becoming 3'-4' long before the fruit ripens; disk of the 

 staminate flower broad-oblong; stamens numerous: disk of the pistillate flower deep cup- 

 shaped, nearly entire; ovary ovoid, rounded at 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 i' long. 



A tree, 50-70 high, with a trunk occasionally 3 in diameter, gracefully spreading and 

 ascending branches forming a broad open head of wide-spreading branches, and slender often 

 pendulous branchlets, pale green and glabrous or puberulous when they first appear, soon 

 becoming glabrous, and light yellow during their first season. Winter-buds narrow, acute, 

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

 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; southwestern California (Mill Creek, above 

 Forest Home, San Bernardino Mountains) and southern and central Arizona; widely dis- 

 tributed through northern Mexico (var. Jonesii Sarg.) ; well distinguished from the other 

 Cottonwoods of the United States by its small fruit. 



Often planted as a street tree in the towns of southern Arizona. 



10. Populus texana Sarg. 



Leaves thin, glabrous, broadly ovate, gradually narrowed, long-pointed and acuminate 

 at apex, truncate at base, coarsely crenately serrate below the middle, entire above, 3'-3j' 



Fig. 126 



long and 2j'-2' wide; petioles slender, compressed, l'-2^' in length. Flowers not seen. 

 Fruit: aments slender, glabrous, 2^'-3' long; fruit oblong-ovoid, acute, deeply pitted, 

 glabrous, thin-walled, 3-valved, %' in length; disk slightly lobed; pedicel slender, -rV~f m 

 length; seeds ovoid, acuminate, T y long. 



A tree up to 60 high, with a trunk sometimes 3 in diameter, stout more or less pendu- 

 lous branches and stout glabrous pale yellow-brown branchlets. Winter-buds acuminate, 

 glabrous. 



In canons and along the streams of northwestern Texas, where it appears to be the 

 onlv Cottonwood. 



