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no less natural genera or assemblages of species. Nor are 

 Grasses, as one clear natural order, and Umbelliferous 

 plants as another, less strikingly evident among vegeta- 

 bles. Bernard de Jussieu and Linnaeus concurred in 

 tracing out several of these natural orders. But Linnaeus, 

 who long survived his learned friend, at length became 

 persuaded, that neither our knowledge of the species and 

 genera of plants, nor the discriminative powers of the 

 human mind, were as yet adequate to the forming a ge- 

 neral system of such orders ; nor even to define, perhaps 

 any one of them, beyond a possibility of doubt or excep- 

 tion. Genera may, in a vast number of instances, be 

 clearly and technically defined with almost mathematical 

 precision ; but scarcely any natural order, however di- 

 stinctly perceptible, has yet been reduced to irrefragable 

 definition in words. This being the case, it is manifest 

 that no assemblage of such orders can serve for the ana- 

 lytical investigation of unknown plants. 



That object is attainable by simple and indisputable 

 principles only, which keep clear of the ambiguities of na- 

 tural orders, and which require no previous knowledge of 

 any such combinations. The purpose of an artificial sy- 

 stem, or any system for the use of a learner, is, to make 

 out the characters, name, and history of some unknown 

 plant. 



The chief object of the study of natural orders is to 

 enable us to understand and to teach others the limits of 

 natural genera. 



It is of great consequence that these two very distinct 

 objects should not be confounded, for they cannot be as- 

 similated. A simple and ready artificial arrangement, on 

 the plan of an alphabet, is necessary for those who, hav- 

 ing found a plant, want to discover its name and history, 

 by investigation of its technical characters, according to 

 rules which are easily learned, and require no previous ex- 

 pei'ience. 



Such is the sole aim of the popular system of Linnaeus. 

 Being founded on parts which every plant in perfection 



