THE POPLARS. 
57 
to SO large a size or so moderate an age as the Abele. Its 
height, when full grown, is from forty to eighty feet, and after 
fifty or sixty years its heart-wood begins to decay, and its 
destruction is then hastened by the attacks of such internal- 
feeding insects as the caterpillars of the Goat-moth and the 
Wood Leopard-moth. The leaves on the branches are broadly 
egg-shaped, approaching to round, the waved margin cut 
into teeth with turned-in points. In one form (var. villosd) 
the leaves are covered beneath with silky or cottony hairs ; 
\ in the other form (var. glabra) they are almost smooth. 
The leaves on the suckers are heart-shaped, without teeth. 
