Populus. SALICACE.E. 105 



The buds, as well as those of several other species, are covered with 

 a resinous exudation, which is occasionally used medicinally as a substitute 

 for turpentine and other balms. 



322. Populus angustifolia, James. 

 Black Cottonwood. 



Black Hills of Dakota, eastern and southwestern Montana, east Hum- 

 boldt and Shoshone Mountains, Nevada, Rocky Mountains of Colorado, 

 and on the ranges of southwestern New Mexico and eastern Arizona. 



A small tree, 15 to 18 metres in height, with a trunk rarely exceeding 

 0.60 metre in diameter; borders of streams, between 0,000 and 10,000 

 feet elevation. 



Wood light, soft, weak, close-grained, compact ; medullary rays nu- 

 merous, obscure ; color brown, the sap-wood nearly white. 



323. Populus trichocarpa, Torr. & Gray. 

 Black Cottonwood. Balsam Cottonwood. 



Valley of the Fraser River, British Columbia, and probably much 

 farther north, east to the eastern base of the Bitter Root Mountains, 

 Montana, south through Washington, western Oregon and California to 

 the southern borders of the State. 



A large tree, 24 to GO metres in height, with a trunk 1.20 to 2.10 

 metres in diameter ; banks of streams and bottom-lands below 6,000 feet 

 elevation; very common and reaching its greatest development in the val- 

 leys of the lower Columbia River and the streams flowing into Puget 

 Sound, here the largest deciduous tree of the forest. ■ 



Wood very light, soft, not strong, rather close-grained, compact ; 

 medullary rays thin, hardly distinguishable ; color light dull brown, the 

 sap-wood lighter, nearly white ; in Oregon and Washington largely 

 manufactured into staves of sugar-barrels, wooden-ware, etc. 



324. Populus monilifera, Ait. 



Cottonwood. Necklace Poplar. Carolina Poplar. Big Cotton- 

 wood. 



Shores of Lake Champlain, Vermont, south through western New 

 England to western Florida, west to the eastern base of the Rocky 

 Mountains of Montana, Colorado, and New Mexico. 



A iarge tree, 24 to 51 metres in height, with a trunk 1.20 to 2.40 

 metres in diameter ; low, moist soil ; the common cottonwood of Texas 

 and the western plains, bordering all streams flowing east from the Rocky 

 Mountains. 



Wood very light, soft, not strong, close-grained, compact, liable to warp 

 in drying, difficult to season ; medullary rays numerous, obscure ; color 

 dark brown, the thick sap-wood nearly white ; largely used in the manu- 

 facture of paper-pulp, for light packing-cases, fence-boards, and fuel. 



