EVOLUTION OF PLANTS 



CHAPTER I 



INTRODUCTION 



WITH the acceptance of the theory of evolution, the 

 question of the origin and affinities of the manifold 

 forms of life making up the organic world becomes of 

 absorbing interest to the biologist, and the hope of 

 solving some of these problems has been the great in- 

 centive to much of the most brilliant work, both of 

 zoologists and botanists, during the latter half of the 

 nineteenth century. 



When we survey the vast assemblage of living organ- 

 isms, the thought of arranging these in orderly sequence 

 seems hopeless ; and indeed when we take into account 

 how many forms must have disappeared and left no 

 trace behind, it must be admitted that the task is one 

 whose completion, if ever reached, must lie in the dis- 

 tant future. Nevertheless the data are slowly but 

 surely accumulating through the efforts of biologists 

 whose patient researches are constantly adding to our 

 knowledge, both by the discovery of new forms and 

 by a more thorough examination of those already 

 known. The constant improvement in the technical 

 appliances for research, such as the microscope and 



B 1 



