326 



Fig. 2. 



one of tlie two factors entering with each gamete. In the follo- 

 wing year a single F2 family was raised and consisted of 51 

 normal fertile, 30 normal sterile, 33 cretin fertile, and 1 cretin 

 sterile. 1 ) The cretin character behaved as recessive to the normal 

 flower, but the relative distribution of the different characters 

 evidently pointed to some form of repulsion between the normal 

 flower and fertility. Had it not been for the appearance of 

 the single sterile cretin we could have regarded this case as 

 one of complete repulsion between the factors N and F. The 

 problem was to account for the sterile cretin ; and at the time we were 

 inclined to regard it as due to an unaccountable failure of repulsion 

 between N and F. Lack of opportunity prevented us from 

 following up this case in 1910, but in the present year we sowed 

 the seed of the rest of the Fi plants harvested in 1908 and 

 obtained details of eight more families which are set out in the 

 accompanying table (Table I). 



x ) In this family and in one of those subseqnently grown both light 

 and dark axilled plants occur ed. In each case the dark axil went in from 

 the fertile cretin parent, and in F 2 there is some coupling between the 

 dark axil and fertility. The nnmerical results howerer are complex and 

 must be left over for discussion until more material is available. 



