ru&ri- lamarckir sdntit- 



gigas albida oHlonga, nervis ana nanclla, lata lans 



4th Generation 



1895-1896 1 15 .176 



3d Generation 

 1890-1891 



2d Generation 

 1888-1889 



1st Generation 

 1886-1887 



FIG. 247. Mutation in evening primrose 



In 1886 Hugo de Vries gathered the seeds from a number of evening primroses 

 (CEnothera lamarckiana) which he found growing in a vacant lot. These plants are 

 natives of North America, and probably escaped from some Dutch garden. From seeds 

 thus obtained about 15,000 ordinary lamarckiana plants were grown, and in addition five 

 peculiar dwarfed individuals (nanella) and five with broad leaves (lata). These two sets 

 were different from the parents as well as from any other known varieties of CEnothera. 

 Later these new forms appeared again in very small numbers from very large sowings of 

 lamarckiana seeds (third and fourth generations). In the third sowing (1890) another 

 new form appeared, having reddish veins (rubrinervis). In the same manner new types 

 have appeared in each 'succeeding generation, and some of these types appeared anew 

 several times. By means of careful breeding it was possible to preserve the new quali- 

 ties, and to recombine them with one another and with the contrasting characters of the 

 parent type according to the Mendelian principles 



