Dendrology 



49 



The leaves are single and are arranged on all sides of the 

 branch. They are short, stiff, and usually sharp pointed. 



THE KINDS OF SPRUCES 



The firs 



Of the nine firs in the United States, two occur in the 

 eastern part ; one of these, the balsam fir or more commonly 

 known as the balsam, is northern. This tree is readily 

 recognized from the nature of its cones and the resin 

 blisters in the bark. The firs do not have resin in the 

 wood as do the pines and spruces. This resin or balsam 

 that occurs in the bark is collected, and furnishes the 

 Canada balsam of commerce. The cones stand upright, 

 and when mature they fall to pieces, leaving nothing on 



