228 BETULA. 



found in Iceland, and in fact its limits in Europe may be 

 said to be bounded only by vegetation itself. In Asia 

 also it holds a wide domain, inhabiting Siberia as far 

 as the Altaic mountains, and appearing also in the far 

 distant Himalayas. In North America Loudon supposes 

 that it appears in the form of Bet. populifolia, though 

 botanists consider that tree to be a distinct species ; if, 

 however, plants of Bet. populifolia are frequently raised 

 from the seed of the common Birch, Bet. alia, as Loudon 

 affirms to be the case, their identity, in our opinion, is 

 proved by so convincing a fact. The most beautiful form 

 of the Birch is that of the pendulous or weeping variety, 

 or, as some call it, variation, which prevails in the highlands 

 of Scotland and mountainous parts of Wales. It generally 

 grows with greater rapidity, and attains a larger size than 

 the common sort ; on this account, as well as for its supe- 

 rior beauty, its seed is always collected by the nurserymen 

 in preference to that of the other, so that purchasers are 

 now almost certain of obtaining plants of this improved 

 and superior kind. 



Sir T. Dick Lauder has made a remark, which does 

 not appear to have been noticed by other writers, " that 

 in young Weeping Birches, there is a certain degree of 

 roughness on the spray, as if it were the coagulation 

 of a gum exuded from the pores, that never failed to 

 indicate to us the tree which was ultimately to turn 

 out of the pendulous variety."" This we have long ob- 

 served in regard to the plants purchased from the nur- 

 series, and the result has almost invariably proved as 

 Sir T. D. Lauder describes it. This exudation also exists, 

 but in an inferior degree, in Bet. popiilifolia, another indi- 

 cation, we think, of its common origin with the Bet. alba ; 



