59 



XXI. 



SALICINE^. 



THE POPLAR. 



POPULUS. 



The white poplar, P. alba, the black poplar, P. 

 nigra, and the asp, P. treimila, are all believed to 

 be indigenous to this country. " Some derive the 

 " word popiilt's," it is said, " from paipallo, to 

 " vibrate or shake; others suppose that the tree 

 " obtained its name from having been used in 

 " ancient times to decorate the public places in 

 " Rome, where it was called arbor popiili, or the 

 " tree of the people." 



Like its ally the willow, the poplar is a 

 dioecious plant, producing only one sex on an 

 individual tree ; but in the poplar the leaves are 

 wide and short, whereas in the willow they are 

 long and narrow. The bark of the poplar, too, — 

 except that of the Lombardy poplar and of some 

 old black poplars — is inclined to be smooth, while 

 the bark of the willow is rough. 



The leaves of the poplar are triangular. They 



