62 Elementary Species 



genera, are equally artificial or conventional. 

 Incidentally it is to be said " that current 

 misconceptions as to the extreme range of fluc- 

 tuating variability of many native species have 

 generally arisen from a failure to recognize the 

 composite nature of the forms in question/' as 

 has been demonstrated by MacDougal in the 

 case of the common evening-primrose, Onagra 

 biennis. " It is evident that to study the be- 

 havior of the characters of plants we must have 

 them in their simplest combinations ; to investi- 

 gate the origin and movements of species we 

 must deal with them singly and uncomplicated/' 



