THE BIRCH FAMILY. BETULACE^ 



THIS family includes, not only the birches, bu. the alders and 

 hazelnuts. Many of its members are shrubs, but others are 

 large, usually very graceful trees. 



The leaves are simple, alternate and variously toothed, but 

 seldom lobed. The flowers are small, arranged in dense cat- 

 kins, the sterile and fertile both growing on the same tree. 

 The sterile catkins are usually slender and drooping, the fertile 

 erect and somewhat rigid, often remaining on the tree long 

 after the seed has been discharged. 



I. THE BIRCHES 

 Genus Bet-ula 



This is the type of the family and has all the family character- 

 istics plainly marked. Its members are mostly but not always 

 trees. Several northern species are shrubs. The trees are 

 tall and graceful with slender branches, the branchlets often 

 drooping. 



The bark, while thick and rough on the old trunks of some 

 species, is usually comparatively thin, the outer part being made 

 up of paperlike layers. 



The wood is close-grained, hard and splits freely. Owing to 

 the resemblance in the grain it is often used as a substitute for 

 mahogany in furniture making. Both bark and wood con- 

 tain an oil which makes them burn readily. 



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