352 PARKS AND PLEASURE-GROUNDS. 



attained by a mere botanical succession, or by the inter- 

 mingling of many genera in tbe same group, or where 

 the place assigned to each plant is determined by its 

 stature, and not by its generic character. Though we 

 disapprove of the intermingling of genera with each 

 other, we hold that many of them may be put in juxta- 

 position. There are even certain alliances in which the 

 numbers of genera and species are so limited that they 

 may very properly form combined groups, as in the 

 following associated pairs: 8-9, 10-11, 19-20, 27-28, 

 29-30. 



Between the different groups of trees and shrubs 

 lawns of varying breadth should be interposed; the 

 broader lawns being partly occupied with clumps of low- 

 growing trees and shrubs, and the narrower glades being 

 left entirely open. The distance at which the trees and 

 shrubs should be planted in their respective groups 

 must depend on the magnitude which the individual 

 species acquire in this country. While there should be 

 space for a pretty ftdl development of each, they should, 

 generally speaking, not be placed at such distances apart 

 as to prevent various members of the group from coming 

 into contact with each other, when they have attained a 

 considerable size. At the same time the finer and more 

 graceful forms should be so stationed as to appear to the 

 greatest advantage ; and to those that are less important 

 may be assigned inferior places. The margins of the 

 large groups may be feathered by smaller ones, or by 

 single trees and shrubs ; but this must be done so irre- 

 gularly, and with such a leaning forward in the major 

 mass, or with such other relation between it and the 

 single trees, as to obviate the effect of dotting, which, as 

 the besetting sin of arboretum s, ought to be carefully 

 guarded against. 



