324 



EVOLUTION, GENETICS, AND EUGENICS 



Only one form, O. scintillans, that appeared eight times, is not 

 constant as are the other species. When self -fertilized its seeds 

 produce always three other forms, 0. scintillans, O. oblonga, and 

 O. lamarckiana. It differs in this respect from all the other elementary 

 species, which mutate not more than once in ten thousand individuals. 



Genera- O. rubri- O.Lamarck- O. scinlil- 



tions 0. gisas 0. albiJa 0. oblonga nervis iana O. nanella O. lata lans 



Gen. 8 

 l8gg 



Gen. 7 

 i8g8 



Gen. 6 

 l8g 7 



Gen. 5 

 l8g6 



Gen. 4 

 iSgs 



Gen. 3 

 l8go-gi 



Gen. 2 



l388-8g 



Gen. i 

 1S86-87 



Mutants and Number observed in 

 different years 



O. Lamarck- 

 iana 

 The mu- 

 tating 

 stem form 



Mutants and Number 

 observed in different years 



Fig. 77. — Diagram showing in condensed form the genealogy of the Oenothera 

 Lamarckiana family and its various mutants during successive years. The numbers 

 under each type represent the number of new types observed each year. {From 



To7ccr.) 



From the seeds of one of the new forms, O. laevifolia, collected 

 in the field, plants were reared, some of which were O. lamarckiana and 

 others O. laevifolia. They were allowed to grow together, and their 

 descendants gave rise to the same forms found in the lamarckiana 



