THE MUTATION THEORY 



357 



Only one form, 0. scintillans, that appeared eight times, is not 

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

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



Fig. 59. — Diagram showing in condensed form the genealogy of the Or;/<)///<T(7 

 lamarckiana family and its various mutants during successive }'ears. The numbers 

 under each type represent the number of new types observed each year, {from 



Tower.) 



From the seeds of one of the new forms, O. laevi folia, collected 

 in the field, plants were reared, some of which were 0. lamarckiana and 

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

 descendants gave rise to the same forms found in the lamarckiana 

 family, described above, namely, O. lata, elliptica, nannclla, rubri- 

 nervis, and also two new species, 0. spatulata and leptocarpa. 



In the lata family, only female flowers are produced, and, there- 

 fore, in order to obtain seeds they were fertilized with jK^llen from 

 other species. Here also appeared some of the new species already 



