PRINCIPLES OF CLASSIFICATION. 31 



pear indicated by Nature herself. Some are very 

 evident, as Grasses, Umbelliferous Plants, Com- 

 pound Flowers, the Orchis tribe. Palms, Ferns, 

 and Mosses. Others are more obscure, and many 

 plants cannot yet be referred to any such Orders 

 or Classes. 



78. Artificial ones (76) are contrived for human con- 

 venience, to assist the memory, and to promote the 

 determination and discrimination of plants. Such 

 constitute the Linnsean system, founded on the 

 Stamens and Pistils (58, 59); those of Tournefort 

 and Rivinus upon the Corolla (54); and those of 

 Ray, and several other authors, upon the Fruit 

 (61) and Seed (62). 



79. Linnseus first pointed out the distinction betwixt 

 a Natural and an Artificial System; but Bernard 

 de Jussieu and his nephew Antoine Laurent de 

 Jussieu, first formed and published a Natural Sys- 

 tem, reduced to a regular form upon scientific 

 principles. 



80. Linnaeus contended that human science was not 

 yet competent to give definitions, or technical cha- 

 racters, of Natural Classifications. 



81. Adanson however undertook this, and A. L. 

 de Jussieu has founded his System, published 

 at Paris in 1789, upon such characters; which 

 though incomplete, and liable to various excep- 

 tions, is of great use as a key to a Natural Ar- 

 rangement (79). In proportion, however, as it 

 serves this purpose, and is dependent on defini- 



