278 CHARACTERS OF GENERA. 



perception, solidity of judgement, and perspicuity of 

 expression, always meet in the same person. Those 

 who excel in this department are named by Linnreus, 

 Phil Bot.sect, 152, theoretical botanists; those who 

 study only species and varieties, practical ones. 



In methodical arrangement, whether natural or arti- 

 ficial, every thing must give way to generic distinc- 

 tions. A natural system which should separate the 

 species of a good genus, would, by that very test 

 alone, pove entirely worthless ; and if such a defect 

 be sometimes unavoidable in an artificial one, con- 

 trivances must be ^adopted to remedy it ; , of which 

 Linnreus has set us the example, as will hereafter be 

 explained. 



Generic characters are reckoned by Linnaeus of three 

 kinds, \he factitious, the essential, and the natural, all 

 founded on the fructification alone, and not on the 

 inflorescence, nor any other part. 



The first of these serves only to discriminate genera 

 that happen to come together in the same artificial 

 order or section; the second, to distinguish a particular 

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

 natural order, and consequently from all other plants; 

 and the third comprehends every possible mark com- 

 mon to all the species of one genus. 



The factitious character can never stand alone, but 

 may sometimes, commodiously enough, be added to 

 more essential distinctions, as the insertion of the 

 petals in Agrimonia, Engl Bot. t. 1335, indicating 



