PART IV. 



SYSTEM or LINNJEUS, &c. 



According to the Linnsean system, the vegetable 

 kingdom is divided into Classes, Orders, Genera, and 

 Species. See page 4. 



Observation. 1 These divisions arid subdivisions of the vegeta- 

 ble kingdom enable a student to find out the name and history of 

 stii unknown plant, in the most expeditious manner, by referring 

 it, in the first place, to its class, and to its order in that class ; 

 then determining- to what p-enus it belongs, and what species it 

 is in the genus, which is the individual : whereas, without method 

 and system, he would have been under the necessity of searching 

 over the descriptions of all the plants known. 



2. The Classes and Orders are called artificial divisions, in oppo- 

 sition to natural ones, because they are professedly constructed to 

 serve the purpose of mere convenient divisions, stamped by a de- 

 finite mark by which the individuals of each may be at once recog- 

 nised ; and because they, in many instances, bring together, in the 

 same division, plants which are dissimilar, agreeing- only in the 

 assumed technical character of such division, as the Elm and Car- 

 rot, which, notwithstanding they are very unlike, belong to the 

 same class and order merely, because th?y have each the same 

 number of stamens and pistils; whereas natural divisions bring 

 together such only as are similar, allied by numerous affinities, as 

 the Carrot and Parsnip. The Genera are founded on natural af- 

 finities, and are natural of course. The genera are naturally di- 

 vided into species See observations on Natural Orders. 



It is no objection to artificial divisions, that they bring together, 

 in the same division, objects which are dissimilar; but their 

 characters should be so constructed, that they should not separate 

 those which are very closely allied, as the various species of the 

 same genus. 



