SYSTEM OF DECANDOLLE. 163 



are necessarily collective, and relative differences often 

 depend on relatively different combinations only ; one or 

 other, or even all the elements, may in turn be absent, 

 and yet the concurrence of several, or of the majority, 

 be rightly deemed conclusive." (Burnett.) 



The signs of the other divisions of the system are 

 sufficiently marked upon the table. The following is 

 the arrangement of the different natural families con- 

 taining the officinal plants of the Ph. Lond. under this 

 system, and which are described in their turn. 



