28 HANDBOOK 148, U.S. DEPARTMENT OF AGRICULTURE 



often in almost pure stands; at higher altitudes, Cascades, 

 and in mountains of e. Oreg., e. Wash. 



quaking aspen (Populus tremuloides). 

 12. Leafstalks round in cross section, grooved; leaves egg- or 

 pear-shaped, pointed at tip, slightly heart-shaped or rounded 

 at base, dark .green and shining on upper surface, pale or 

 often whitish with a "bloom" on under surface; seed pods 

 globe-shaped, hairy, splitting into 3 parts; large, fast-growing 

 trees, mostly less than 50 feet high (to about 125 feet in 

 best sites), with deeply furrowed bark; river bottoms or 

 along streams, mostly w. of Cascades, Oreg., Wash., oc- 

 casional in mountains, e. Oreg., e. Wash. 



black cottonwood (Populus trichocarpa) . 



Black cottonwood 



