214 Studies in Indian Cotton 



In all other cases, as will subsequently appear, dominance is incomplete. 

 The fact may be contrasted with the observation of Balls (1) in another 

 group of cottons in which the impure form is recognisable as of a pale 

 lemon yellow distinct from the full yellow of the parent. 



3 (6). The red colouring matter of the sap. 



In types 3 and 11a red anthocyanic colouring matter is present in 

 the sap and communicates an intense red to the entire plant — stem, 

 leaves and flowers. This colour is especially marked in the young 

 chlorophyll bearing tissues, but it is also distinct in such organs as the 

 stigma, anther and fruit. The young leaves are of an intense purple 

 which fades, however, as the leaf developes until in the mature leaf, 

 only the ribs and veins show the colouration distinctly, the lamina 

 retaining merely a slight, and, in cases, barely distinguishable, colour. 

 From the remaining types this colouring matter is absent and their 

 foliage is green, and the petals either white or yellow. 



The Fi generation of a cross between either of the types 3 and 

 11, and, in fact, any type in which the red colour occurs, and the 

 types in which the colour is absent, bears the red colour which may 

 be said to be dominant. The intensity of the red colour is, however, 

 sufficiently diminished to render the cross readily distinguishable from 

 the parent. 



The F2 generation is readily separable into two sections according 

 to the presence or absence of the red colour. The proportion of 

 coloured individuals to colourless which has been obtained in the 

 experiments under review are given in Table II, 



Among the coloured individuals, however, there is a considerable 

 range of intensity in the red sap. In the foliage this is apparent in 

 the extent to which the colour suffuses the leaves. In the least 

 intense form the mid-rib and two main lateral ribs of a young, but 

 fully expanded, leaf are suffused, and the minor veins and lamina green. 

 Further intensification occurs when the larger veins appear as red lines 

 set in the green lamina, and finally the whole lamina may be suffused 

 as in the red parental type 3. The records of this character in its 

 relation to foliage character show the colours as limited to (a) the ribs, 

 (6) the veins, or (c) the lamina diffused throughout. While the limits 

 between these three are not very distinct, the division offers a fair 

 guide to the purity or reverse of the plant under consideration in 

 r3gard to this character. 



Table III (a) shows that in 5 cases out of 66 an error was made in 



