STUDIES IN BOTANY 



living things) applies to both plants and animals. There 

 is so much confusion in the use of this word that it should 

 be understood at the outset that biology deals with all 

 living things, and that plants and animals are two groups 

 of living things. To begin with the thought that plants 

 are alive and at work is important, because this fact gives 

 meaning to their forms and structures and positions. For 

 example, the form and structure and position of a leaf have 

 no -meaning until it is discovered how these things enable 

 the leaf to do its work. 



3. Plants and human needs. It is evident that the 

 material welfare of the human race is largely based upon the 

 work of plants. Not only do they furnish the fundamental 

 food supply for all living things, but in innumerable minor 

 ways they contribute to the necessities of human life. This 

 important relation to human needs has resulted in grouping 

 plants into those that are useful and those that are not, 

 the inference often being that the latter are not so im- 

 portant for study as the former. If useful plants are to be 

 made to yield the largest returns under cultivation, it is 

 absolutely necessary to understand their structure and 

 work. It is also true that plants can explain one another, 

 and many " useless" plants can interpret useful ones. As a 

 rule, the simpler plants are not used by man, but they are 

 necessary to explain the more complex ones that he does 

 use. It is further true that the scientific study of plants, 

 whether useful plants or not, suggests methods of making 

 useful plants more useful. For example, the practical work 

 of agriculture can be improved only as the scientific work 

 with plants points out the way. The most effective way 

 to study useful plants, therefore, is to study the structure 

 and work of plants in general. 



4. Plant work. Although many different kinds of work 

 are being carried on by plants, all the work may be put 

 under two heads : nutrition and reproduction. This means 



