236 St'udies in Indian Cotton 



definite reason exists for the correlation between these two measurable 

 and apparently distinct characters, and it is permissible to select the 

 one that appears to be more reliable for the purpose of recording the 

 habit of the plants under consideration. 



While in neither case has an accurate method of record been 

 obtainable, the date of appearance of the first flower is at once more 

 readily determined and obtainable in a larger number of instances. 

 The measure of the length of the vegetative period, therefore, probably 

 affords a means of indicating the habit of the plant which is more 

 accurate than the direct record of the percentage of monopodial second- 

 ary branches, and has been adopted to record the behaviour of this 

 character when plants of the two groups are intercrossed. 



The habit of the offspring from a cross between monopodial and 



sympodial types. 



In the ^1 generation derived from a cross between a plant belonging 

 to a monopodial and one belonging to a sympodial type, the length of 

 the vegetative period is intermediate between those of the two parental 

 types. This is shown by Table XXVI in which the relative lengths of 

 the vegetative periods of the F^ generation and of the two parental 

 types are detailed. This table further shows that while the Fy^ genera- 

 tion is intermediate in this respect, it does not hold a position 

 corresponding to the mean of the two parental values but in all cases 

 approaches the sympodial type. In this table the seasonal variation is 

 eliminated by comparison of the F^ generation with the offspring of the 

 parent plants. 



In the F^ generation the plants form a continuous series in which 

 every stage from early flowering to late flowering forms occurs. It is 

 noticeable, however, that while those individuals of the F^ series which 

 have the shortest vegetative period are in flower as soon as, or even 

 before, the plants of the parental type, in no case does the vegetative 

 period equal in length that of the monopodial parental type. In other 

 words, while the full sympodial type appears comparatively frequently 

 the full monopodial type only rarely does so. The divergence from the 

 mean length of the parental vegetative periods noticed in the F^ gene- 

 ration is here even more marked. 



Diagram 2 illustrates these results for a single instance of a cross 

 between a monopodial and a sympodial type. Owing to the seasonal 

 variation above noted it is impossible to compare the periods for 



