OP GENERA. 365 



contrivances must be adopted to remedy it ; 

 of whicli Linnecus has set us the example, aa 

 will hereafter be explained. 



Generic characters are reckoned by Lin- 

 naeus of three kinds, the factitious, the es- 

 sentiai, and the natural, all founded on the 

 fructification alone, and not on the inflores- 

 cence, nor any other part. 



The first of these serves only to discrimi- 

 nate genera that happen to come together in 

 the same artificial owhr 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 common to all the species of one genus. 

 The factitious character can never stand 

 alone, but may sometimes, commodiously 

 enough, be added to more essential distinc- 

 tions, as the insertion of the petals in Agri- 

 monia, Engl. Bot. t. 1335, indicating xha 

 natural order to which the" plant belongs, 

 which characier, thou ah essential to that or- 

 der, here becomes factitious. 



Linnaeus very much altered his notions of 

 the essential character after he had published 



