Handbook of Tkrks of the Koethfkn States and Canada. 121 



The Paper Birch, west of the Rocky Moun- 

 tains, is said to attain a heiglit of 120 ft. with 

 trunk from 3-4 ft. in thickness, hut elsewhere 

 rarely exceeds 7U or SO ft. in lieight. When 

 isolated from other trees it de\elops a full 

 rounded and usually irregular top of many 

 branches. The bark of the larger branches 

 and young trunks is laminate, smooth and of 

 creamy or i\ory whiteness, marked with long 

 horizontal raised lenticels. As the trunk en- 

 larges the bark becomes more or less streaked 

 and blotched with blackish and the outer layers 

 separate and roll back in large ragged sheets. 

 On very old trunks the bark at base becomes 

 broken into large closely appressed irregular 

 scales. It inhabits rich slopes and ornaments 

 the banks of northern streams and lake-shores 

 from the Atlantic to the Pacific, ranging north- 

 ward to the Arctic Circle. With the northern 

 Indians its bark, impervious to water, is an 

 indispensable material for the manufacture of 

 their canoes and for many articles for domestic 

 use. 



The w"ood, of which a cubic foot when abso- 

 lutel_y dry weighs 37.11 lbs., is used in the 

 manufacture of wooden-ware, wood-pulp, etc., 

 and is excellent for fuel.^ 



Lrovcs ovate, 2-4 in. long, acute or acuminate 

 at apex, rounded or obtuse (cordate* in var. ronJi- 

 folia Fern. I and entire at liase, doubl.v or ir- 

 rpgularl.v serrate, thicl^ and firm at maturity, 

 glal>rous dark green attove. paler and pubescent on 

 tlie veins and witli black glands beneath. FIuii:rrs: 

 staminate aments %-lVt in. long in winter, finally 

 ."-4 in. long: pistillate aments l-iy^ in. long, 

 slender, with light green scales and red styles. 

 Fruit: strobiles " cylindrical. al)Out 1 Vj in. long, 

 drooping, glalirous, middle lolie of scales longer 

 than broad ; nutlet much narrower than its wings. 



1. 



Syn. /;. 



II. 4:: 



11 Ait, 







