CHAPTER VI 

 THE CLASSIFICATION OF PLANTS 



202. We now come to that part of the subject in which 

 we are to consider the different kinds of plants to be 

 found in the world. Botanists now know over 233,000 

 kinds, a number which is too vast to be remembered in 

 detail by any one and yet even the beginner may learn 

 much about them by taking up their study properly. 



Of Relationship 



203. It is now known that all the kinds of plants are 

 related to one another. By this we mean that traced 

 back far enough all plants have a common ancestry, in 

 other words they have descended from earlier identical 

 or similar forms. This is what we know as Evolution, 

 and in thinking of the great numbers of plants we regard 

 them as related to one another because they have 

 descended recenth' or remotely from common ancestors. 



204. In Botany we try to group plants according to 

 their relationships, much as we group people by their 

 relationships. This requires that as we study plants we 

 should constantly keep in mind the fact that they are 

 less or more alike just as their relationship is remoter or 

 nearer. And this is what we call Phylogeny, that is, the 

 racial history of the groups of plants. So what follows 

 in Chapters VII to XX is an attempt to present selected 

 representatives of the groups of plants in such a sequence 

 as will suggest their relationship and path of development. 



205. It must be remembered that plants have been in 

 existence for a very long time, and that many, or possi- 



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