PRELIMINARY DISCOURSES. XXV 



accordingly been employed by the early Botanists, in constructing 

 systems of classification.* 



Some have based the arrangement on the texture and size of 

 plants classing them in divisions of Herbs, Shrubt, and Trees; others, 

 again, on the structure and form of the Calyx, the Corolla, the Fruit, 

 &c. or on the presence, or absence, of some important organ: And, 

 in our own times, the favorite object following JUSSIEU and DE 

 CANDOLLE is to arrange plants strictly according to their affinities, 

 to group together, in Orders and Tribes, those which are most 

 nearly related in all the features, and properties, which constitute 

 character. These various Systems may be all regarded as forming 

 only two kinds, namely, the Artificial, and Natural Methods; 

 though, in point of fact, the artificial methods are more or less 

 founded in Nature, and in the most perfect natural arrangements, 

 yet devised, artificial sections, or groupings, are still resorted to, as 

 useful helps and expedients. "What we call a natural method" 

 says the excellent Prof. GRAY "is so termed merely because it ex- 

 presses the natural relationship of plants as far as practicable ; for 

 every form yet contrived, or likely to be devised, is to a considerable 

 extent, artificial." 



The great and obvious defect of the methods called artificial, con- 

 sists in their being founded on the fewest possible characters, 

 whereby plants are arbitrarily brought together without reference 

 to their intimate structure, or general relationship with each other ; 

 and hence it often happens, in such methods, that plants which are 

 essentially dissimilar, are arranged side by side ; while kindred species 

 are widely separated. This defect is inherent in all artificial systems ; 

 and therefore, the most of them are only tolerable on account of 

 the facilities which they afford in determining unknown genera and 

 species or ascertaining the names of particular plants. The system, 

 however, which was devised by the celebrated LINNAEUS, has the 

 merit of combining some of the advantages of both the artificial and 

 natural methods ; and will probably long continue to be employed, 

 as a convenient and useful help to the investigations of young 

 Beginners. It is, indeed, very remarkable, how many natural 

 families of plants are kept nearly entire, under the Sexual System. 

 The Linnaean classification, of the flowering plants, is founded on 

 the characters of two of their most important organs, namely, the 



* The late Professor B. S. BARTON, in his Elements of Botany, has given a Syn- 

 opsis of seventeen different methods of artificial arrangement, from that ofCAESAL- 

 PISUS, "the Father of Systematic Botany" which was published in 1583 down to 

 the Linnaean method, as modified by THUXBERG, near the close of the last century. 

 As a matter of curiosity, they are worth consulting. 



