76 TREES 



courages them to fresh activity. The only way to get rid 

 of the young growth that springs up about an old tree is to 

 use the grubbing-hoe thoroughly and patiently. 



Poplar blossoms, borne in catkins, show the close re- 

 lationship between this genus and the willows. The 

 leaves, however, are always broad and leathery, and set on 

 long stems. Twenty -five species are known, twelve of 

 which are American. 



The White Poplar 



Populus alba, LinUo 



The white poplar is sometimes called the silver-leaved 

 poplar because its dark, glossy leaves are lined with cot- 

 tony nap. This sprightly contrast of light and shade in 

 the foliage is most unusual, and very attractive in early 

 spring; but the leaf -linings collect soot and dust, and this 

 they carry to the end of the season — a fact which should 

 not be forgotten by those considering the advisability of 

 planting this tree in a city where much soft coal is 

 burned. 



The white bark of this European poplar reminds us of 

 the birch family, though it has no silky fringe shedding 

 from the surface. The leaves often imitate the maple in 

 the divisions of their margins, justifying the name "maple- 

 leaved poplar." 



As a dooryard tree this species has a wider popularity 

 than it deserves. The wind breaks the brittle branches, 

 and when these accidents threaten its life, the tree sends up 

 suckers which form a grove about the parent trunk, and 

 defy all efforts to eradicate them, until the grubbing-hoe 

 and axe have been resorted to. 



