io BULLETIN 205. 



low soils. Thus far, the ash has not been very much used in cities. Of 

 the various species of this tree, the white ash is much the best. 



HACKBERRY. 



The hackberry is another of our common native trees which deserves to be 

 more frequently planted. It is shapely, not choice as to soil, grows rapidly, 

 resists drought, is easily grown from the seed and easily transplanted, and 

 is free from any serious diseases. Various leaf- eaters and gall insects attack 

 its foliage, and its branches are often disfigured by distortions attributed 

 to a gall-mite and a powdery mildew, but none of these troubles seriously 

 injure its value as a shade producer nor endanger its life. It is said to be 

 frequently used for shade in the west. 



SWEET-GUM. 



The sweet-gum develops rapidly and well in a great variety of soils and 

 is practically free from insects and fungus attacks. The beauty of its foli- 

 age in autumn more than offsets the extra care required in transplanting 

 and the litter caused by its fruits. 



KENTUCKY COFFEE-TREE. 



This tree can be grown only in rich damp soil. I have seen it very rarely 

 in cities, but the specimens I have observed were very handsome and I 

 think it deserves a trial in soils to which it is adapted. 



Bui. 



The merits of this most popular shade tree are so well known that I need 

 not record them here. It should not be planted however, to any great 

 extent in the large cities of the East, unless provision is made for regular 

 and thorough spraying and other precautions taken to hold in check its 

 various insect enemies, among which the leopard moth and the imported 

 leaf-beetle are the most destructive. The elm is adapted to wide streets 

 and requires deep moist soil. Its condition in many of our cities is far from 

 satisfactory, and its use as a street-tree is in many localities attended with 

 considerable risk. In towns and villages where the leaf-beetle is as yet 

 unknown, the elm is grown with great success. 



Other species of elm are occasionally planted in our cities, but none are 

 equal to the American elm in general fitness for street use. The slippery 

 elm, for example, cannot be used on account of its mucilaginous bark, which 

 is relished by the small boy as a substitute for chewing gum ; and the 

 English elm, which does well in Berlin and Hamburg, is so greedily attacked 

 by the elm leaf-beetle when planted here that it is not only useless for pur- 

 poses of shade, but forms a centre from which this insect easily spreads to 

 neighboring trees of our own species. Incidentally, the English elm is 

 sometimes used as a trap tree in working against the elm leaf-beetle. 



SILVER MAPLE. 



The silver maple is a graceful tree of very rapid growth and possesses 

 many qualities of an ideal street tree ; but it is especially subject to injuri- 



