EXOGENOUS SERIES BROADLEAF WOODS. 75 



at higher latitudes than other American broadleaf trees. It is 

 easily recognizable by its white bark and is particularly beautiful 

 during the winter because of contrasts that are then more 

 apparent. (The bark of this species was preferred for canoes 

 because of its pliability, and its availability in large pieces where 

 it was most needed. JThe layers of other barks, as Betula 

 populifolia, do not separate so easily from one another, nor do 

 they divide so readily from the trunk. 



The yellow and sweet birches (Betula lutea and Betula lento) 

 are the American birches most prized for woods. The European 

 birches often afford the cheapest hard-woods of their districts, 

 and these woods are used for sabots, plates, spoons, wheels, 

 pegs, buttons, and furniture. The Russians reduce birch logs 

 into veneers, that are then glued across one another (see page 

 125 so as to form thin planks ; the planks are used for tea chests, 

 chair bottoms, and the like. Burls, that sometimes occur on 

 trunks, afford figured woods that are turned into bowls, cups, or 

 mallets. Europeans also use birch indirectly, as in tanning, 

 smoking meat, etc. The bark and leaves of some species are 

 widely esteemed as domestic remedies. Oils are separated by 

 distillation.* The sweet sap drawn from some of the birches is 

 nsed as a beverage. 



Birch trees may be known by their more or less laminated 

 bark with its peculiar long horizontal lenticles or dashes. The 

 leaves of the several birches differ but little, but the decided 

 colors exhibited by their barks give names and serve to distin- 

 guish the species. Nine of the twenty-four known species of 

 birch occur in North America; six are trees and the others low 

 shrubs. Betula is said to be derived from bitumen. 



* Wintergreen oil was formerly distilled from the leaves of the wintergreen, 

 but almost all " natural oil " is now obtained from the sweet birch (Betula lento). 

 (Forestry and Irrigation, December, 1905). These oils and their manufactured 

 products consist almost entirely of Methyl salicylate. 



