INTRODUCTION 3 



able to do their work; 1 and thirdly, the stem has 

 also to bear the flowers. The flowers themselves have 

 quite a different duty to perform. Their business 

 is to produce the seeds, and so to provide a supply of 

 new wallflowers for the future. We see, then, that 

 the organs which we have mentioned are of two kinds. 

 On the one hand, the root, stem, and leaves do work 

 for the benefit of the particular plant to which they 

 belong ; these we call the vegetative organs. On the 

 other hand, the flowers are concerned in the produc- 

 tion of fresh plants; they are therefore called the 

 reproductive organs. 



One important division of Botany, then, is concerned 

 with such questions as those which we have just 

 roughly indicated. We aim at finding oub how a plant 

 lives, what different kinds of work it has to do in 

 order to live and to produce others of its kind, and 

 by means of what organs the work is done ; also what 

 is the structure of these organs by which they are 

 enabled to perform their office. All these questions 

 belong to Physiology in its widest sense. Physiology 

 is concerned with the question what a plant does, and 

 what its various organs do. The answer to such 

 questions must be obtained by experiment. The study 

 of structure, or Anatomy, is from this point of view 

 a necessary auxiliary to physiology. 



But we can also look at plants from a different 

 point of view. Suppose, for example, that instead 

 of considering the Wallflower alone, we compare it 



1 It is often convenient to speak of the stem and leaves together as 

 the shoot. 



