GENERrC CIIAUACTI'.RS. 285 



used throughout his Genera Plantarum, a work now su- 

 perseded by the essential characters in his Systema Veg- 

 etahilium, and therefore in some measure laid aside. 

 The disadvantages of the natural character are, that it 

 does not particularly express, nor direct the mind to, the 

 most important marks, and that it can accord only with 

 such species of the genus as are known to the author, 

 being therefore necessarily imperfect. This kind of 

 character is, however, admirable for the illustration of 

 any difficult natural order. Mr. Gawler's elucidations 

 of the Ensatce, Sword-leaved plants, Jnnals of Botany, 

 V. 1. 219, and Curt. Mag. afford excellent specimens of 

 it, serving as a store of facts and observations for follow- 

 ing systematical writers. 



Specific characters should be. constructed on similar 

 principles to the generic ones, as far as regards certainty, 

 clearness and conciseness. The genus being first well 

 defined, we are to seek for characters, not mentioned 

 among the generic marks, for distinguishing the species. 

 A specific difference for a solitary species of any genus, 

 is therefore an absurdity. Linnaeus at first intended his 

 specific definitions should be used as names ; but the in- 

 vention of trivial names happily set aside this inconve- 

 nient scheme. On this account however he limited 

 each to twelve words, a rule to which all philosophical 

 naturalists have adhered, except in cases of great neces- 

 sity. Nor is the admission of one or two words beyond 

 the allotted number reprehensible, provided the whole 

 sentence be so neatly and perspicuously constructed, 

 that the mind may comprehend it, and compare it with 

 others at one view ; but this can hardlv be done when 



