328 PARKS AND TLEASFEE GROUNDS. 



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 in- 

 ferior 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 irregularly, 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 arboretums, ought to be carefully guarded 

 against. 



On ground with a flat surface, and soil of a uniform 

 quality, a combined botanical and pictorial grouping 

 of the whole collection will be the ])rincipal object of 

 study. Certain shrubs will require special soils, such 

 as peat and sand, and these should be formed for them. 

 Where there is a considerable diversity of surfaces 

 and soils, attention ought to be directed not only to 

 the grouping on the principles already indicated, but 

 also to the effect of the proposed distribution in rela- 

 tion to the surface which is to be covered, and to the 

 s.oils on which the plants are to grow. We must con- 

 sider w4iat group will appear to most advantage on a 

 given hill, or knoll, or slope, or hollow, and whether 

 also the soils of these may not be more suitable for 

 one order or family than for another. A fine hollow 

 with moist soil might seem, at first sight, to promise a 

 propitious site for willows, alders, and poplars ; and 

 yet, on examination, it may be found tliat such. locality 

 may be better adapted, both in reference to beauty 

 and luxuriance of growth, for the hardier sorts of what 



