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It is proposed to plant from one to three examples of each species of tree on open lawn, and with sufficient space about each to allow it to attain its fullest size with unrestricted expanse of branches; the effect of each tree is also to be exhibited iu masses, so as to illustrate its qualities for grouping. Space is provided to admit of at least three specimens of every native which is known to flourish in the United States north of North Carolina ; also for several specimens of every shrub ; these latter, how- ever, except in particular instances, are not expected to be planted singly, but in thickets, and as under wood to tlie coppice masses ; as may best accord with their natural habits, and be most agreeable to the eye. Further details of this part of the design will be found in the explanatory guide to the arboretum, submitted with the plan, in which the proposed arrangement of all the trees is set forth in order.

(OLMSTED, F.L. and VAUX,CALVERT “GREENSWARD” Description for the improvement of Central Park. 1858. New York.p 34)