Popultts. SALIC ACEiE. 103 



316. Salix lasiolepis, Benth. 

 Willow 



California, — valley of the Klamath River, southward through the 

 western portions of the State, reaching in the Sierra Nevadas an eleva- 

 tion of 3,500 to 4,000 feet above the sea. 



A small tree, sometimes 12 to 18 metres in height, with a trunk 0.45 

 to 0.50 metre in diameter, or northward and at high elevations reduced to 

 a low shrub ; leaves varying greatly in shape and breadth (vars. angusti- 

 folia and latifolia, Anders.), or toward its southern limit often persistent 

 until spring (S. Hartwegi, Benth.). 



Wood light, soft, not strong, close-grained, compact ; medullary rays 

 numerous, thin ; color light brown, the sap-wood nearly white ; somewhat 

 used as fuel, especially in the southern part of the State. 



317. Salix Sitchensis, Sans. 

 Silky Willow. . 



Alaska, southward near the coast to Santa Barbara, California. 



A low, much-branched tree, rarely exceeding 8 metres in height, with 

 a trunk 0.30 to 0.45 metre in diameter, or more often a straggling shrub ; 

 low, wet soil, borders of streams and ponds. A form with narrow oblau- 

 ceolate leaves is var. augustifolia, Bebb. 



Wood light, soft, close-grained, compact ; medullary rays numerous, 

 thin ; color light red, the sap-wood nearly white. 



318. Populus tremuloides, Miehx. 

 Aspen. Quaking Asp. 



Northern Newfoundland and Labrador to the southern shores of Hud- 

 son Bay, northwest to the Great Bear Lake, the mouth of the Mackenzie 

 River, and the valley of the Yukon River, Alaska ; south in the Atlantic 

 region to the mountains of Pennsylvania, southern Indiana and Illinois, 

 and northern Kentucky ; in the Pacific region south to the valley of the 

 Sacramento River, California, and along the Rocky Mountains and in- 

 terior ranges to southern New Mexico, Arizona, and central Nevada. 



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

 0.G0 metre in diameter ; very common through British America, and 

 spreading over enormous areas stripped by fire of other trees ; in the 

 Pacific region very common upon moist mountain slopes and bottoms 

 between 6,000 and 10,000 feet elevation; the most widely distributed 

 North American tree. 



Wood light, soft, not strong, close-grained, compact, not durable, con- 

 taining, as does that of the whole genus, numerous minute scattered open 

 ducts ; medullary rays very thin, hardly distinguishable ; color light brown, 

 the thick sap-wood nearly white ; largely manufactured into wood-pulp ; 

 in the Pacific region sometimes used for fuel, flooring, in turnery, etc. 



