128 MASS. EXPERIMENT STATION BULLETIN 170. 



FIG. 1. The Lancaster elm. 



to lawns and roadsides, but not at all to mowings. The high branching 



habits of this tree render it the best type we have for streets on which 



there are numerous wires. In recent years it has become infested with 



such insects as the elm-leaf beetle, 

 and most disastrously by the leopard 

 moth. It has suffered more of late 

 from the effect of drought than any 

 other tree, and extreme cold has 

 affected its root system to a con- 

 siderable extent. These defects have 

 been the means of discouraging its 

 planting. The elm has a habit of 

 occasionally shedding its leaves and 

 twigs, and is sometimes affected by 

 a leaf fungus (Dothidella). 



SLIPPERY ELM (Ulmus fulva). 

 Occasionally the slippery elm is 

 planted by mistake for the American 

 elm. It is, however, a much smaller 

 and inferior tree. 

 ENGLJSH ELM (Ulmus cam.pestris) . This tree, which attains a large 



size, is a handsome species, and was formerly planted more extensively, 



at least in certain localities. It is, 



however, more susceptible to the elm- 

 leaf beetle than our native species. 



Other elms which may be mentioned 



here are the Scotch elm (U. montana), 



which is occasionally seen; the Cork 



elm ( U. racemosa) , a tree of fairly good 



size with a corky bark and of slow 



growth; and the Japanese elm (U. 



japonica), a handsome, symmetrical 



tree of rapid growth, little known in 



America. Although affected to some 



extent by the elm-leaf beetle, this elm 



gives promise of becoming a valuable 



shade tree. 



ROCK MAPLE (Acer saccharum). 



The maples as a whole have been more 



extensively used for street planting 



than trees of any other group. The 



rock maple, like the elm, has been ex- 

 tensively employed as an ornamental 



tree; indeed, there is no species that has been used more widely for 



lawns and avenues than the rock maple. It is one of our handsomest 



trees, being characterized by unusual symmetry and dense foliage. It 



FIG. 2. Type of feathered elm. 



