62 Elementary Species 



genera, are equally artificial or conventional. 

 In other words we may state " 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, Oeno- 

 thera biennis. " It is evident that to study the 

 behavior of the characters of plants we must 

 have them in their simplest combinations; to 

 investigate the origin and movements of species 

 we must deal with them singly and uncompli- 

 cated." 



