Vg eS a ee a 
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. 
Or 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 recently 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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