gigas 



albida oblonga rubri- lamarck- nanella lata scintLl- 

 nervis iana lans 



176 



3d generation 

 1890 - 1891 



2d generation 

 1888 - 1889 



1st generation 

 1886 -- 1887 



4th generation 

 1895 - 1896 



10,000 



15,000 



8 14,000 60 



73 



U Parental type 



MUTATIONS IN THE EVENING PRIMROSE 



From 1886 on, Hugo de Vries planted seeds from the common evening primrose. 

 Among thousands of new plants grown each year he found from one to several 

 individuals that departed in some definite way from the parental type. He gathered 

 and planted the seeds of these deviates, and in the course of time had a number of 

 distinct strains. From these experiences he developed the mutation theory to explain 

 how new species originate 



