CROSSINGS IN MELAMUM-VIOLETS 265 



guide. When both those factors nrv absent tlie whole of tl»e spur- 

 petal becomes dark-yellow. I think it necessary, however, to make 

 additional investigations. 



In the crossings 3 X 10 and 10 X 2ô plants are also found 

 with dark-yellow spur-petals. Of the first mentioned crossing 7 

 were dark-yellow and 45 light-yellow, viz. the ratio 1 : 6,i.i. Here 

 the deviation is greater than the probal)le error of the dihybrid ratio. 

 In the latter cross 3 individuals had a dark-yellow spur-petal of 35 

 in all. Thus, the ratio 1 : 10,:r.. which lies within the statistically 

 allowed range. 



One plant in the /^^-g^^iK^'ration had the violet colour confined to 

 the end of the upper petals. It looked quite like Wittrock's maculata 

 forms. Its genetics, however, was not investigated as it very 

 soon died. 



I have grown the F2-generation of three crosses between different 

 varieties of V. arvensis, viz. 2X4, 2X13 and 26 X 27. All these 

 lines were »typical» V. arvensis. The Fj -generation of the cross 2X4, 

 as well as the F 2, numbering 188 individuals, were all of the same 

 yellow colour as the parents. The same was the case with the cross 

 2X13 whose F-, counted about 50 plants and 26 X 27 with 439 F.- 

 individuals. Thus, no synthesis of anthocyan had taken place. 



Besides these crosses I have grown the Fi of several other crosses. 

 In no case a synthesis of anthocyan was observed. 



THE INHERITANCE OF THE GREEN SPOT OF THE STYLE. 



Two of my /rjco/or-lines had a green spot on the anterior part 

 of the style. When crossed with types devoid of the dark spot this 

 character was found to be dominant. This was the case in 8 Fj- 

 generations of crosses between types with and without the spot. 



I have investigated two F:;-generations as to the inheritance of 

 this character. In Fo of the cross 2 X ,10 I found 130 individuals w ith 

 the spot and 40 without. This gives the observed ratio 2,938 : 1,062; 

 the theoretical is 3 : 1 rfc 0,io95. Thus, the agreement is good. 



In the other cross (3 X 10) 38 plants with dark spots were ob- 

 tained and 7 without. The observed ratio 2,30.3 : 1,607 did not agree 

 very well with the theoretical: the deviation is a little more than 

 twice the probable error. The number of individuals, however, was 

 rather small and therefore this deviation may be less significant. 



In crosses between types lacking the spot on the style I never 



