238 



HEREDITY AND ENVIRONMENT 



in the Fi generation had pink flowers and from 

 these in the F 2 generation there came white- 

 flowered, pink-flowered and red-flowered forms 

 in the proportion of 1 white : 2 pink : 1 red, 

 as shown in Fig. 50. This is a better illustra- 

 tion of Mendel's principle of splitting than is 



Fig. 50. Results of crossing white-flowered and red-flow- 

 ered races of Mirabilis Jalapa (four o'clocks) giving a pink 

 hybrid in F x , which when inbred gives in F 2 1 white, 2 pink, 

 1 red. (From Morgan, after Correns.) 



