Description of Trees 177 



Black Poplar (P. nigra), Fig. 97. A most rapid grow- 

 ing tree of a pyramidal growth and dark-green leaves. 

 Trees started from cuttings in 1874 were in 1892 more 

 than 2 1 feet in diameter and 60 feet high. It has, how- 

 ever, developed a very serious fault in that the lower 

 leaves are attacked by a leaf-rust. As this disease is con- 



FIG. 97. Black or Italian Poplar. 



fined largely to the lower leaves, there is no difficulty in 

 checking it, if not wholly preventing, by spraying with the 

 Bordeaux mixture. 



Lombardy Poplar (P. nigra, var. italica), Fig. 98. It is 

 perhaps more planted than any other species. While young 

 it is clean and its strict habit of growth makes it desirable 

 for screens and wind breaks, but as it grows older the lower 



