236 CLASSIFICATION. 



order or section ; the second to distinguish a particular 

 genus, by one striking mark, from all of the same natu- 

 ral order, and consequently from all other plants ; and 

 the third comprehends every possible mark common to 

 all the species of one genus. 



The factitious character can never stand alone, but 

 may sometimes, commodiou«ly enough, be added to 

 more essential distinctions, as the insertion of the pe- 

 tals in Agrimonia, indicating the natural order to which 

 the plant belongs, which character, though essential to 

 that order, here becomes factitious. 



The essential character comprehends all the distinc- 

 tions requisite to discriminate each genus from every 

 other in the system, only avoiding a repetition at every 

 step of the characters of the artificial class and order, 

 which stand at the top of each page, and are not always 

 essential to the character of the genus. This is the 

 kind of generic character now universally adopted, and 

 indeed the only one in common use. The learned Jus- 

 sieu has given it the sanction of his approbation and 

 adoption, as far as its plan is concerned, throughout his 

 immortal work, subjoining in a different type such cha- 

 racters and remarks as belong to the habit, or refer to 

 other circumstances. 



The natural character seems to have been, at one 

 N time, what Linnaeus most esteemed. Its disadvantages 

 are, that it does not particularly express, nor direct the 

 mind to, the most important marks, and that it can ac- 

 cord only with such species of the genus as are known 

 to the author, being therefore necessarily inipe feet. 

 This kind of character is, however, admirable for the 

 illustration of any difficult natural order. 



Specific characters should be constructed on similar 

 principles to the generic ones, as far as regards certain- 



