100 Mr. Roscoe oti Artificial and Natural 



Linnceiis exhibit any associations more revolting to his con- 

 ceptions, or which would tend more decisively to convince 

 him that, whatever may be their pretensions, these systems 

 are in fact equally artificial, and that their assumed natural 

 affinities are nothing more than a partial resemblance, founded 

 on some peculiarity of habit or conformation, which may serve 

 to decide its situation in a nomenclature, but has often little 

 or no relation to the real and essential nature of the plant ? 



II. If such be the fact, our inquiry will now take a different 

 shape. It is no longer a question as to the superiority of one sy- 

 stem over another, but a question of degrees as to the superior 

 execution of a similar method. Let us then, whether we choose 

 to denominate them both natural or both artificial, briefly com- 

 pare the rival arrangements of Linnaeus and Jussieu. 



The most important difference between these two methods 

 consists in a preliminary distinction made by Jussieu, by which 

 he divides the vegetable kingdom into three departments, 

 to each of which he applies a separate mode of arrangement, 

 whereas Linnseus applies his method indiscriminately to the 

 whole. By the plan of Jussieu we are in the first place to 

 ascertain whether the plant which we examine rises from the 

 seed without a cotyledon, with one cotyledon, or with two co- 

 tyledons * ; and having determined this point, we then pro- 

 ceed by other rules to distinguish the individuals in each de- 

 partment. By that of Linnaeus we take the plant without any 

 regard to its mode of germination, and from the parts of fruc- 

 tification immediately determine its character, and assign it to 

 its proper genus. That the mode in which plants arise from 

 the seedf, or, more strictly speaking, that the seed itself, of 

 Avhich the cotyledons are formed, affords a true natural distinc- 

 tion, cannot be doubted ; but in estimating the advantages of 

 this distinction, we must also estimate its disadvantages, and 

 form our decision upon the whole result. The object attained 



by 



* This distinction it may be observed was made by Linnaeus himself, as 

 the foundation of his Regnuni Vegetabile ; with the necessary and indeed 

 indispensable addition of the Polycoti/ledones. 



" Tribus vegetabiUum tres vulgo numerantur. 

 Monocott/ledones. Fruges 1. 2. 3. 



Dicotylcdo7ics. Plantae 4. 5. 



Poli/cotijledo7}ci!. Rhizophora. 



Acoti/lcdones. Cryptogamae 6. /• 8. 9." 



Linn. Reg. Veg. 3. 

 t In his Pldlosophia Botanica, Linn;eus has carried this method much 

 further than Jussieu has done ; having divided the Monocotyledones into 

 perforatic. Gramina. 



unilateralc^. Palniic. 



reductac. C'cpa. 



And 



