212 



MENDELISM 



in combination with C and R, produces the purple 

 or Picotee colour (blue), whilst its absence (b) in pre- 

 sence of C and R is accompanied by the appearance 

 of the red colours Painted Lady and tinged white. 



Purple Invincible and Painted Lady are regarded as 

 intensified forms of Picotee and tinged white respec- 

 tively. The presence of the second factor (T) is attended 

 by the development of the full colours purple and 



CR 



cR 



Cr 



CR 



cR 



Cr 



cR 

 cR 



cR 

 cr 



Cr 

 Cr 



Cr 

 cr 



cr 

 cR 



cr 

 Cr 



cr 

 cr 



FIG 1 6. 



The shaded squares represent coloured plants, the blank squares 

 white plants. 



Painted Lady ; its absence (t) causes the appearance of 

 the diluted forms Picotee and tinged white. 



B and T may be present when either C or R or both 

 are absent ; the resulting plant has then white flowers. 

 And it is interesting to notice that the ultimate recessive 

 white, containing c r b t, occurs only once among 256 

 individuals of F 2 . The whole apparently complex system 

 of floral colours is thus explained by the simple Men- 

 delian behaviour of four separate pairs of allelomorphs. 



Bateson and his collaborators have, therefore, provided 



