PART III 



CLASSIFICATION AND ECONOMICS 



PLANTS are so abundant and the number of different kinds 

 is so great that some system of classification is necessary in order 

 to conduct our studies in the most satisfactory manner. Fur- 

 thermore, it is necessary that this classification shall be the same 

 throughout the world, so that students of botany may work in 

 harmony. The economic plants are distributed throughout the 

 entire plant kingdom, but, of course, the great majority of them 

 are to be found among the flowering plants. 



