126 STUDIES IN INDIAN COTTONS 



The Experiments {A).— The Colour of the Corolla. 



The corolla of the cotton flower consists of five petals arising 

 from the base of the staniinal column. The petal is frequently, 

 and in the true Indian cottons invariably, possessed of a deep red, 

 or purple eye situated on the claw. In the extra- Indian cottons 

 this eye may be absent, and in this case the petal is self-coloured. 

 The presence or absence of the ' ' eye ' ' appears to be independent 

 of the general colour of the petal and requires to be treated 

 separately, 



Omitting for the moment consideration of the eye, the petal 

 may be yellow, white or red. The latter colour is present in Types 

 3 & 1 1 only and is not limited to the petals alone, but is here a local 

 manifestation of the presence of a red sap colour which occurs 

 throughout the plants of these types and will ho more conveniently 

 treated in detail in a following section (C). 



The two petals, then, may be either white or yellow, and of 

 the latter type two forms are readily distinguished. In the one 

 the colour is a full yellow, described in the subsequent text simply 

 as ' yellow," while in the other, found only in Type 10, the colour is 

 very hght — a condition which will be denoted below as ' pale-yellow.' 



The yellow colour is dependent on a colour — producing factor 

 which, according to its presence or absence, gives rise to a simple 

 pair of alellomorphic characters, of which the presence of the colour — 

 producing factor is dominant in botli cases. That is. the yellow 

 is dominant both to pale-yellow and to white. 



In Table I are given the results obtained from a cross between 

 Type 8 (yellow) and Type 10 (pale-yellow), while in Table 11 is given 

 the offspring from a cross between Type 4 (yellow) and Type 

 (white). In both cases the numbers are small and insufficient to 

 give reliable iiuiiiciical values to indicate llic jtiopoitioii existing 

 between the pairs of characters. A clearei- indication is given in 

 Table MI. which is derived from the crosses between Type 3 and 

 Type 10 and between Type 3 and Types 7 <fe 9. These crosses are 

 dealt with in fullei- detail l)eIow. since, owing to the presence of 

 the red colouring matter found in the sap of Type 3, a pair of 

 factors is here involved. 



