APPLICATION OF PRINCIPLES. 247 



by a higlily refined analysis and synthesis of characters, 

 are made to comprise alliances and classes. These suc- 

 cessive combinations_, then, give rise to what ^\e may 

 call generic, ordinal, allied, and dassific groupings; 

 the last however we mention chiefly for the sake of 

 completeness, because, though carefully preserved, it will 

 be almost invisible, except in one or two cases, on ac- 

 count of the multitude of subordinate members which 

 it includes. Eveiy one will admit the propriety of 

 planting each genus by itself, and this accordingly is the 

 first step in the arrangement. But the genera, as spread 

 out on the ground, may be combined into orders ; and 

 these orders, again, may be made to occupy such posi- 

 tions that the allied races, or '' alliances,^^ may be mar- 

 shalled together in space, and may be exhibited to the 

 eye in lining presence as well as presented to the under- 

 standing in theory. It is to the proper collocation of 

 the orders and alliances that attention must be chiefly 

 directed in the scientific treatment of the arboretum. 



A consideration of the Sjmopsis will bring out other 

 important results. By tracing the numbering of the 

 orders and alliances, as quoted from '^The Vegetable 

 Kingdom ' of Dr. Lindley, the reader ^\'ill obseiwe that 

 many of the orders, alliances, and even classes, which 

 exist in a complete system of plants, are excluded from 

 our list by the conditions imposed by om- cold climate 

 and the arborescent growth of the subjects employed. 

 The orders that remain are often found in a sadly muti- 

 lated state. In the Fabacece, for example, — the old 

 " pea tribe,^^ or the Papilionaceous order, as it was wont 

 to be called, — the genera, as estimated in ^ The Vegetable 

 Kingdom,^ amount to 467, while we have been able to 

 assign only twenty -five as available to our present pur- 



