CROSSINGS IN MELANILM-VIOLKTS 



275 



TABLE 13. The corrchdion between the upper petals (ind the ' 



spiir-j)et(il. 



r = + 0,74 



petals and the labellum of about the same size as the small-flowering 

 parent while only a few of them reach the size of the large-flowering 

 parent. However, it is also necessary to assume the existence of 

 factors with a positive effect. In the large-flowering type the larger 

 flowers were dominant to the smaller, as is mentioned above. 



Thus, it seems necessary to assume the existence of inhibiting 

 factors for the quantitative characters in the flower. The question 

 now becomes pressing if this inhibiting effect is due to diffe- 

 rent factors for each character, or if one and the same factor 

 exercises its influence in all characters. This is very easy to establish. 

 If the small petals and the thin labellum in the Fi-generation is due 

 to one single factor with a diffuse effect — or to several factors 



