PART II 



THE KINDS AND RELATIONSHIPS OF 

 PLANTS 



CHAPTER IX 

 THE PHYLOGENETIC CLASSIFICATION OF PLANTS 



THE study of any science presents both analytic and 

 synthetic aspects. By analysis we resolve single structures 

 and processes back as nearly as possible to their ultimate 

 elements. The methods are often elaborate and technical, 

 but are those by which most new knowledge is won. To 

 this phase of Botany, Part I of this book was devoted. By 

 synthesis, the data supplied by analysis are assembled, corre- 

 lated, classified, and welded together into a systematic body 

 of knowledge, the continuous development of which is the 

 logical end of all scientific study. To a synopsis, necessarily 

 brief, of this phase of Botany, Part II of this book is devoted. 

 To most people it forms the more interesting phase of the 

 science, dealing as it does with the kinds, habits, uses, classi- 

 fication, names, and other features of plants, which distin- 

 guish them as living beings and the companions of man on 

 the earth. 



The first requisite of systematized knowledge is classifi- 

 cation. When accurately studied, plants are found to exhibit 

 resemblances to one another in various degrees, such that 

 they fall naturally into groups, and groups within groups, 

 expressible in systems of classification. Of these systems 

 there are two, closely interlocked but distinct in character, 



391 



