EXOGENOUS SERIES— BROADLEAF IVOODS. 85 



Black Cottonwood. Populus Irichocarpa Torr. and Gr. 



Nomenclature. (Sudworth. ) 



Black Cottonwood (Oreg., Cottonwood (Oreg., Cal.). 



Cal.). Balm Cottonwood (Cal.). 



Balsam Cottonwood, Balm 

 (Oreg.). 



Locality. 



Pacific coast region, Alaska to California. 



Features of Tree. 



A large tree sometimes one hundred and fifty feet in height and 

 four to six feet in diameter. 



Color, Appearance, or Grain of Wood. 



Heartwood light dull brown, sapwood nearly white, compact 

 structure. 



Structural Qualities of Wood. 

 Light, soft, weak. 



Representative Uses of Wood. 

 Staves, woodenware (local). 



Weight of Seasoned Wood in Pounds per Cubic Foot. 



23- 

 Modulus of Elasticity. 



1, 580,000. 

 Modulus of Rupture. 



8400. 



Remarks. 



Largest deciduous tree of Puget Sound district (Sargent). 



