CHAPTER X 



GENERAL OUTLOOK ON THE FLORA 

 OF THE LAND 



THE foregoing Essays are apparently disjointed, 

 and aloof from one another. But just as a circle 

 may be defined by three or more detached points, 

 and be drawn so as to establish a clear relation 

 between them, so the subjects of the preceding 

 Chapters, isolated though they at first appear, may 

 be drawn together so as to give some general outlook 

 upon the vegetation around us. Ever since enquiry 

 into the Origin of living forms took shape in theories 

 of Evolution, the underlying principle has been 

 recognised that it is from the simpler organisms 

 that such origins are to be traced. The comparison 

 of these with the more complex has been held to 

 shed light on the genesis of the higher forms. On 

 the other hand, certain conditions and methods of 

 life are known to have led to simplification both 

 of structure, and of the cycle of events in the 

 completed life-story of the individual Thus parasitism 

 leads to simplification of the organs of nutrition. 



