H. M. Leake 213 



a remarkable range of intermediate types, the white-flowered types are 

 recognisably the hardier. On the correlation that apparently exists 

 between hardiness and white flower there is, at present, no definite 

 information available but such correlation would tend to produce a 

 preponderance of whites. 



The figures for the F, generation are unfortunately meagre owing 

 to the large loss (some 90 °/J of young seedlings caused by the early 

 continuous nature of the rains in 1909. The figures are too few to 

 aflford any numerical guide as to the proportion of pure dominants 

 among the yellow F^ plants. They indicate, however, that in the F, 

 generation there occur plants of the type DD giving only yellow 

 offspring and others of the type DR which give both yellow and white 

 offspring. The F^ plants with a white corolla on the other hand give 

 whites only. These results are in entire agreement with those recorded 

 by Fyson (7) and a comparison of the two series of results gives strong 

 evidence as to the part played by vicinism in the field. 



Type 10 is characterised by a flower in which the full yellow of the 

 petals of the type previously considered is replaced by a pale but 

 distinct yellow. This pale yellow behaves as a simple recessive to the 

 full yellow. From a cross between this type and type 8 which is 

 characterised by a full yellow petal the Fy generation is obtained in 

 which the petal is indistinguishable from that of the parent type 8, 

 the full yellow thus being completely dominant. In the F2 out of 

 140 plants, 41 possessed the pale yellow corolla giving a ratio of 

 2'4 plants with full, to 1 with pale, yellow petals. Similarly the full 

 yellow in type 2 appears to be completely dominant over the pale 

 yellow of type 10 giving, in the ^1, plants of which the petal colour 

 is indistinguishable from that of the parent type 2, and, in the F^, 

 91 plants with full yellow, and 66 plants with pale yellow, petals. In 

 both these cases and in the latter especially there occurs a large excess 

 in the actual, over the expected, number of recessives which it is 

 necessary to indicate though without further comment since, through 

 inability to cope with the entire series of experiments as at first 

 planned, a number of crosses, including those involving type 10, had 

 to be abandoned after the F, generation had been recorded and the 

 presence of this excess has not formed the subject of further experi- 

 ment. In no case has the pale yellow flowered been crossed with a 

 white flowered type. 



It may be here noted that these are the only two cases in which 

 complete dominance has been observed in the cottons under consideration. 



15-2 



