THE BIRCH AND THE ALDER. 153 



similarly-laminated bark. The Sanscrit name of 

 this bark, which is used for corresponding purposes, 

 is bhoorja, and hence, in all likelihood, comes our 

 word " birch." Such an etymology is strictly in 

 accordance with that of " poplar," named above, 

 and with several others, and indicates in a pleasing 

 manner the migration from Central Asia westwards 

 of the progenitors of the races of modern Europe. 

 One other circumstance in the physiognomy of the 

 birch is found very frequently to attract attention. 

 It happens in this tree that there is often an ar- 

 rested or impaired development of some portion of 

 the buds. The consequence is that dense bushes 

 of short twigs are produced, concealed when the 

 leaves are open, but in winter very conspicuous, re- 

 sembling deserted crows' nests, and often occurring 

 to the number of twenty or thirty in a single tree. 

 In Scotland these odd developments are termed 

 " witches' knots." 



The leaves of the birch are, as a rule, smaller than 

 those of any other British tree in which the outline 

 is of the same character. The " small-leaved elm " 

 is the only other in which the dimensions are so 

 limited. Yet upon very young trees, and more 

 especially upon those luxuriant and vigorous side- 

 shoots which start from the stumps of old trees that 

 have been cut down, they are often of incredible 

 size. The outline varies a good deal, changing from 

 ovate to almost triangular; but there is always a 



