W. Nrilson Jonks and M. Chevblv Raynkk 200 



any one plant. Thus, hi counts of two B plants the ratio of two- 

 carpellary to three-ear|)('llaiy ovaries was in one case 2 two-carpellary 

 to 123 three-carjiellary : in the other case 3 two-carpellaiy to 100 three- 

 carpellary. In variety (r 100 two-cai'pellary to 3 three-carpeilary is 

 the usual kind of ratio. 



In F„ jDJants from the cross B x (J almost every possible variation 

 in the ratio of twos to threes occurs. 



This suggests that more than one factor is involved. In what 

 follows two factors, Or, and G^, are assumed as a working hypothesis both 

 of which tend to make the ovary two-chambered: thus, a G plant has, in 

 respect to this character, the constitution GiGiG.fi., anfl a B plant has 

 the constitution gi(/i(/^(f<. 



When GiG^i and gig.^ are present in ecjual amounts the ovary is 

 equally likely to be two-carpellary or three-carpellary. 



The number of fruits examined for each $ plant during 1913 and 

 1914 was about 450, though in many cases the number was consider- 

 ably greater. 



The percentage of twos present in the total number counted was 

 adopted as a convenient method of expressing the results for compara- 

 tive purposes. 



In view of a possible criticism that the ratio of twos to threes may 

 vary with cultural conditions or age and vigour of the plants, it is of 

 interest to notice how closely the observations of the two years — made 

 quite independently — agree with one another in most cases. This is 

 illustrated in Table II, which gives the percentage of twos among the 

 eighteen ^ plants of the family obtained from the cross . 



Fi X Fi {(B plant x G plant) x (B plant x G plant)}. 



The other families yield like results. 



It should perhaps be stated here that the figures of the last column, 

 representing summation of the results for two successive years, are 

 those used in the analyses below. 



The genetical results may be summarised as follows : 

 Number of carpels: genetical hehaviour. 

 Fi . Tlieoretical. 



9l9\!!-'9-^ (a plant) x OiGiG-^Go {G plant) 

 I 

 F, all GigiG^y.. 



Jouin. of Gen. v 14 



