AMERICAN WOODS. 



105 



D. Pith rays not visible or else indistinct, even if viewed with uiagmiier. 



1. Wood very soft, white, or in shades of brown, usually with a silky luster .....Cottonwood {poplar). 



ADDITIONAL NOTES TOR DISTINCTIONS IN THE GROUP. 



^ Cherry and birch are sometimes confounded. The high pith rays on the cherry on radial sections readily distin- 

 guish it; distinct pores on birch and spring- wood /one in cherry as well as the darker vinous-brown color of the 

 latter will prove helpful. 



4 pi1 '" 



Beech _.J Sycamore J Birch 



Fig. 12.— Wood of beech, sycamore, and birch 



Fig. 13. —"Wood of maple 



Fig. H.— "Wood of ( lm. a rod < 1m ; b white elm ; c winged olm. 



Two groups of birches can be readily distinguished; though specific distinction is not always possible. 



1. Pith rays fairly distinct, the pores rather few and not more abundant in the spring wood; wood heavy, 



usually darker - Cherry birch and yellotv Urdu 



2. Pith rays barely distinct, pores more numerous and commonly forming a more porous spring-wood zone; 



wood of medium weight - Canoe or paper birch. 



The species of maple may be distinguished as follows : 



1, Most of the pith rays broader thm the pores and very conspicuous „....•.„— - „ - Sugar maple. 



