WILLOW FAMILY 



coarsely serrate, and in the pubescence which when young is 

 found on both leaves and petioles. The buds and apex of 

 the growing shoots are heavily laden with a fragrant gum- 

 my secretion. 



COTTONWOOD 



PSpulus deltoides, PSpulus monilifera. Pdpulus angulhta. 



Deltoides, like the Greek letter delta, refers to the shape of the 

 leaf ; vionilifera refers to the necklace-like pistillate ament ; 

 aiigiilata refers to the angled stem of the shoots. 



Comparatively rare and of small size in the eastern states, the 

 Cottonwood is the largest and most abundant tree along the streams 

 between the Appalachian and the Rocky Mountains, reaching the 

 height of a hundred feet. 



Bark. — On old trees ashy gray and deeply divided 

 into broad rounded ridges broken into scales which 

 cever the light yellow inner bark. On young stems 

 and branchlets smooth light yellow green tinged with 

 red. Young shoots become angular in their second 

 year. 



Wood. — Dark brown, sapwood nearly white ; light, 

 soft, close-grained, not strong. Warps badly in dry- 

 ing ; is now used only in the manufacture of paper- 

 pulp, cheap packing cases and fuel. Sp. gr., 0.3889 ; 

 weight of cu. ft., 24.24 lbs. 



Leaf Buds. — Resinous, shining, acute, chestnut 

 brown, half an inch long. Flower-buds ovate, ob- 

 tuse, half an inch long. 



Leaves. — Alternate, three to five inches in length, 

 deltoid or broadly ovate, truncate, slightly cordate or 

 wedge-shaped at base, crenately-serrate with coarse, 

 incurved, glandular teeth. They come from the bud 

 involute, gummy, fragrant with balsamic odor, pale 

 green or tawny, drooping, but at maturity they are 

 thick, bright shining green above, paler green be- 

 neath. In autumn they turn a clear bright yellow. 

 Petioles slender, two to three inches long, compressed 

 laterally, yellow or red. Stipules vary in size, cadu- 

 cous. 



Flowers. — March, April, before the leaves. Stam- 

 inate trees densely flowered, aments three to four 

 inches long, one-half inch thick. Scales are scarious, 



426 



Winter Branch 

 of Cotton- 

 wood, Popu- 

 lus deltoides. 



