108 A MANUAL OF MENDELISM 



Instead of this, however, the progeny of the hybrids 

 turned out to be as follows : 



D D d d 



F f F f 



The hybrid and each of the original parents appeared 

 again in such groups and numbers as are produced 

 by intermediate hybrids. The factors D and f on the 

 one hand and d and F on the other did not separate 

 but behaved in each case as one factor, as is proved by 

 the fact that the combination df was not formed. The 

 only possible explanation is that either D and f or 

 d and F or both are coupled. Again, plants having 

 a red flower with a hooded standard and long-shaped 

 pollen were crossed with other red ones having an erect 

 standard and round pollen. The hybrids were red with 

 long pollen and erect standards. Red being common to 

 both parents, we should expect the usual two-pair set 

 of four groups, as follows (E = erect, h = hooded, 

 L = long, o = round) : 



E E h h 



L o L o 



9:3:3:1 



Instead, however, the hybrids' progeny were as follows : 



E E h h 



L o L o 



