LATENT CHARACTERS 



199 



by the development of the full colours purple and 

 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 266 

 individuals of F 2 . The whole apparently complex system 



CR 



cR 



Cr 



CR 

 cR 

 Cr 



f/% 



cR 

 cR 



cR 

 cr 



Cr 

 Cr 



Cr 



cr 



cr 

 cR 



cr 

 Cr 



cr 

 cr 



FIG 16. 



The shaded squares represent coloured plants, the blank squares 

 white plants. 



of floral colours is thus explained by the simple Men- 

 delian behaviour of four separate pairs of allelomorphs. 

 Bateson and his collaborators have, therefore, pro- 

 vided a complete account of the phenomenon of reversion 

 on crossing, an account which has already been demon- 

 strated to hold good in other instances besides that 

 of the sweet-pea. The facts are expressed in the 

 following manner by their discoverers. ' " Reversion " 

 is thus seen to be a simple and orderly phenomenon 

 due to the meeting of factors belonging to distinct 



