Handbook ok Tkkks of the Xoktiii;i{.\ Statks and Canada. 



This stately tree is llic I;ir<;cst representa- 

 tive of its gemis. soiiictiincs surpassing 100 ft. 

 in heiglit. witli trunk ti-S ft. in diameter. It 

 develops a full wide or roiuuli'd tciji with few 

 massive branches, and these often spreading far 

 out extend their drooping branches and shining 

 dark green leaves over a ver^- wide area. It 

 is confined to the rich moist soil of river bot- 

 toms and the banks of streams and along those 

 of the mid-continental regions it is the largest 

 and most characteristic tree. East of the 

 Alleghany Mountains it is less abundant and 

 a smaller tree: still here and tliere con- 

 spicuously large trees are found. 



The wood is light and soft, a cubic foot when 

 absolutely dry weighing 24.24 lbs., and is used 

 for paper pulp, in the manufacture of lumber 

 for packing cases and for fuel. Owing to ten- 

 dency to warp and ditliculty in seasoning it i-. 

 little valued for lumber. In early days, how 

 ever, before railroads crossed the western 

 plains the pioneer settlers found in the Cotton 

 wood trunks material for building purpo-^i - 

 from the rough stockade to the houses an ' 

 buildings of their first villages.^ 



Leaves broadly deltoid-ovate, H-7 in. long, usual U 

 abruptl.v acuminate at apex, truncate or slighiU 

 cordate at base, crenati'-scrratc. entire at base, at 

 tirst gummy with fragrant exudation but finalh 

 lustrous dark green alxive. [laler beneath; petiole"-, 

 long, slender, and laterally comiiressed. FJoim^ 

 (.\pril-May) : aments short-stalked; staminatc 

 stout and densely flowered, ;;-."> in. long ; stamens 

 numerous: pistillate at first smaller but elongat 

 ing as fruit ripens ; scales glabrous, laciniate 

 Fruit with ovoid 2-4-valved capsules, which libei 

 ates in May their crowded contents of small light 

 brown seeds with cottony coma. 



P. deUfjiden m-eideiitdliy Kydb. is a western foim 

 ranging from 8ask. to Xew Mexico with leaM s 

 broader at base, longer-acuminate and mon 



coarsely toothed with yoiuig 

 light yellow. 2 



1. Syn. PopuUiH munilifera A 



2. A. W., II. 4S. 



5hinui!,, 



3. For genus 



pp. 426-41 



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