CHAPTER X 

 METHODS OF CLASSIFICATION 



Systematic botany, of which systematic pomolo^ry is a part, 

 is concerned with naming:, describing, and chissifying i)lants in 

 groups. The orderly arrangement of plants is classification. 

 Several systems of classification have been in use, and others 

 proposed, but the one which now meets with the approval of 

 scientific workers has as its basis the theory of evolution. It 

 is assumed for the foundation of this system that all plants have 

 descended from a few original forms, or one form, and that the 

 relationships of these descendants can be shown in classification. 

 In this evolutionary scheme the most prominent and the most 

 peculiar structures of the plants are considered with the view of 

 grouping together those which are most similar in a number of 

 structures, taking it for granted that plants nearest related to 

 each other in descent will fall into the same group. This is the 

 Natural System in contradistinction to Artificial Systems in 

 which one structure, or set of structures, serves as a basis of 

 grouping and in which there is no attempt to express rela- 

 tionships. 



The groups employed in the Natural System of classification 

 are : — 



140. Individuals. — A single or particular plant as distin- 

 guished from a group is an indimdxial. If the seeds of an apple 

 are sown, several individual apple-trees may result, which, 

 though never identical, are similar in root, branch, flower, and 

 fruit. Seeds sown from apples grown on another tree bring 

 forth similar plants, showing greater unlikeness from those of 

 the first sowing than the offspring from the seeds from any one 

 apple. Differences between trees become greater until eventually 

 the unlikenesses become more apparent than the likenesses, and 

 another group is proposed, as the pear, possibly, for one set of 

 variants and the crab for another. Such groups, perhaps arti- 



