SWAMP COTTONWOOD 



autumn they turn a clear bright yellow. Petiole slender, laterally 

 compressed, one and a half to two and one-half inches long. Stip- 

 ules caducous. 



Flowers. April, borne in pendulous aments, one and a half to two 

 and a half inches long, from buds formed the season before. The 

 one- flowered scales are deeply divided into five or si& acute lobes, 

 with soft light gray hairs which also cover the disk. Stamens from 

 six to twelve, inserted on a shallow oblique disk with entire margin ; 

 filaments short, slender ; anthers light red. Ovary oblong-conical, 

 light green, hairy ; style short ; stigmas spreading, divided into fili- 

 form lobes. The ovary enclosed in the persistent disk. 



Fruit. Oblong, curved capsule, light green, thin-walled, hairy, 

 two-valved, one-eighth inch long, borne on a drooping ament four to 

 five inches long. Seed minute, dark brown, surrounded by rather 

 short, snowy white hairs. May. 



The Large-toothed Aspen is gregarious, loves to grow in 

 thickets ; its leaves twinkle on the gravelly hill-side or along 

 the river-bottom ; it ripens its long, drooping, necklace-like 

 aments in May as its leaves unfold and in every particular 

 proves itself a poplar. 



The high-sounding name, P. grandidentata, means simply 

 that the teeth of the leaf margin are a little larger than those 

 of P. tremuloides. 



SWAMP COTTONWOOD. BLACK COTTONWOOD. 

 DOWNY POPLAR 



P6pulus heterophylla. 



Rare in New England, common in the south Atlantic states, abun- 

 dant in the lower Mississippi valley. Loves low wet land. In the 

 north is a tree forty feet high, with a rather round-topped head, 

 its maximum height is ninety feet. 



Bark. On old trees, light brown tinged with red, often broken 

 into long narrow plates attached only at the middle ; on young trees 

 divided by narrow shallow fissures into flat ridges. Branchlets con- 

 tain an orange-colored pith, at first are dark red brown or ashy gray, 

 later much darker and roughened by leaf scars. 



Wood. Dull brown, sapwood lighter brown ; light, soft and close- 

 grained. Is now often manufactured into lumber in the west and 

 south and used in interior finish of buildings. Sp. gr., 0.4089; 

 weight of cu. ft., 25.48 Ibs. 



419 



