LATENT CHARACTERS PAS | 
Painted Lady is a well-known colour type which is 
characterized by the presence of a red standard and 
white wings. Picotee and tinged white are also forms 
well known to the sweet-pea fancy. They appear to 
be diluted forms of the purple and Painted Lady types 
respectively, their appearance depending upon the 
presence of a definite diluting factor in addition to the 
factor for the colour in question, or perhaps more 
properly upon the absence of the proper strengthening 
factor which converts Picotee into purple, and tinged 
white into Painted Lady. 
The following explanation of the result so far 
déscribed has now been well established by further 
experiment. In the first place, we may consider all the 
coloured forms together as a single group opposed to 
white. It is now clear that the coloured type of F, is 
due to the meeting together of two factors, one of them 
born by one white parent and the other by the second, 
and it is necessary for both these factors to be simul- 
taneously present in order that any colour may make 
its appearance. We may call these two factors C and 
R, denoting the absence of either by c and 7 respectively. 
By the simple Mendelian behaviour of these two pairs 
of factors C-c and R-r, the ratio of nine coloured 
plants to seven white appearing in F, is readily 
explicable, and the way in which this happens is shown 
in the diagram on the opposite page. 
To explain the presence of the four different types of 
coloured plants which make their appearance in F,, 
two further pairs of allelomorphs are called in. The 
dominant member (B) of one of these, when present 
14—2 
