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 Linnaeus, 

 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, prove entirely worthless ; and if such a defect 

 be sometimes unavoidable in an artificial one, con- 

 trivances must be adopted to remedy it ; of Avhich 

 Linnasus has set us the example, as will hereafter be 

 explained. 



Generic characters are reckoned by Linnaeus of three 

 kinds, the factitious^ the essential^ and the natural^ all 

 founded on the fructification alone, and not on the 

 infloresct^nce, 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 

 fiatural order, and consequently from all other plants; 

 and the third comprehends, every possible mark com- 

 mon to all the species of one genus. 



Thejactitioiis character can never stand alone, but 

 may sometimes, commodiously enougli, be added to 

 more essential distinctions, as the insertion of the 

 petals in Jgrimonia^ EngL Bot, t, 1335, indicating 



