PREFATORY NOTE 



The keen appreciation of the public of 

 the beauties of nature as expressed in the 

 building of parks and public gardens, in 

 the planting of street trees, and in the 

 adornment of private grounds and homes 

 by means of ornamental plants is one of 

 the most distinctive marks of an advanced 

 civilization. The success of these under- 

 takings means the overcoming of many 

 difficulties which the casual observer fails 

 to appreciate. It means not only the se- 

 lection and arrangement of varieties in 

 such manner as to meet with the most 

 sesthetical tastes of the public, but it fre- 

 quently means growing the plants under 

 new environmental conditions, the study 

 of soil and climate, the contest against 

 insects and diseases which continually 

 threaten the existence of these plantings. 



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