INHERITANCE ON CROSSING 



53 



types. The characteristics have, as we say, blended. 

 On rearing the second hybrid generation, 25 per cent, 

 were found to be " Chinese," 25 per cent, were of the 

 " star " form, and the remaining 50 per cent, were inter- 

 mediate like the first cross. This is illustrated in Fig. 7. 

 The sole difference between this result and that 

 obtained with the tall and dwarf types of pea, is that 

 in the one case the hybrid inc 7 ividuals were indistm- 



FIG. 7." Chinese " and " Star " Primulas with the first and second 

 hybrid generations. (After Punnett.) 



guishable from one of the parent types, whereas in the 

 other the hybrids were intermediate in character. 



The process of segregation, however, has evidently 

 been the same in the two instances. In both we get 

 the ratio, in the second hybrid generation of 



25 per cent. " pure," like the one original parent. 



50 



hybrid, like the first cross. 

 " pure," like the other original parent. 



The distribution of the parental characters amongst 

 the individuals of the following generations follows, then, 

 a very simple scheme, instead of being, as was formerly 

 thought, the most irregular of all the phenomena of 

 heredity. 



