COUPLING 109 



Again the hybrids behaved as intermediates. Conse- 

 quently there was coupHng of E and o, or h and L, or 

 both. 



But a case occurred in which three factors were 

 coupled. There is a sweet-pea called Painted Lady 

 in which the standard is erect and the flower red, but 

 the standard is a bright red while the wings are only 

 faintly coloured. Thus the variety may be called 

 bicoloured. There is another variety called Duke of 

 Westminster which has a hooded standard. In this 

 case the colour is purple, but both standard and wings 

 are almost equally coloured. This variety may there- 

 fore be called unicoloured. The following tabular state- 

 ment shows the differences between these varieties : 



Painted Lady Duke of Westminster 



Red Purple 



Bicolour Unicolour 



Erect standard Hooded standard 



When they were crossed, their hybrids were purple 

 and bicoloured, with erect standards ; and we should 

 expect their progeny to have formed the following 

 three-pair set of eight groups : 



27: 9:9:9:3:3:3:1 

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



