408 SYSTEMATIC BOTANY. 



Section 2.— Natueal Systems of Classification. 



The object of all natural systems, as already noticed, is to 

 group together those plants which correspond in the greatest 

 number of important characters, and to separate those that 

 are unlike. The mode in which this has been attempted to 

 be carried out, varies according to the particular views of 

 botanists as to the relative value of the characters furnished by 

 the different organs of plants ; hence it will be necessary for 

 us, before proceeding to describe the more important natural 

 systems, to make some remarks upon this subject. The obser- 

 vations of Dr. Lindley are here so much to the point, that we 

 cannot do better than quote them, although it will be afterwards 

 seen, that we venture, in accordance with the views of many other 

 botanists, to differ in some particulars from that well-known 

 system atist : — 



" The only intelligible principle by which to estimate the 

 respective value of the characters furnished by the different 

 organs is according to their known physiological importance; 

 regarding those organs of the highest rank which are most es- 

 sential to the life of the plant itself; placing next in order those 

 with which the plant cannot dispense if its race is to be pre- 

 served ; assigning a still lower station to such organs as may be 

 absent without considerable disturbance of the ordinary functions 

 of life ; and fixing at the bottom of the scale those parts, or 

 modifications of parts, which may be regarded as accessory, or 

 quite unconnected with obviously important functions. 



" The first office which all organized beings have to perform is 

 that of feeding, for it is thus only that their existence is main- 

 tained. The second is that of propagating, by means of which 

 their species is perpetuated. These being functions of the 

 highest importance, it is reasonable to conclude that the organs 

 pro'\'ided for their proper execution must be of the highest im- 

 portance also, and hence that they are, beyond all others, 

 valuable for the purposes of classification. And, again, be- 

 cause the power of feeding must come before that of propa- 

 gating, it might be conjectured beforehand, that the organs 

 destined for the former operation would afford the first elements 

 of a natural method. But since the act of feeding is very 

 simple in the Vegetable Kingdom, because of the similar modes 

 of life observable among plants, while, on the contrary, the act 

 of propagation is highly diversified, on account of the very 

 varied nature or structure of the parts by which it is accom- 

 plished ; so might we conjecture that the organs of nutrition 

 would afford but few distinctions available for purposes of 



