96 



STUDIES IN INDIAN TOBACCOS. 



the environmental influences, however, both the breadth and 

 the length appear to be similarly affected, and the ratio between 

 the two is therefore less dependent on these influences. The 

 ratio length/breadth has been studied in three crosses (see 

 Tables XXV, XXVI, and XXVII). The results are very much 

 the same as in other characters. In Table XXV the ratio from 

 Type 9 is not given, as it will be evident from Table XVI that 

 no two leaves are alike in this respect. In Table XXIV the 

 most interesting culture is 694 which, although almost uniform 

 in the Fa generation, has shown further segregation in the 

 following year. 



Fig. 1. Leaf shape and position of greatest width. 



In cross Type 16 x Type 35 where the length of the leaves is 

 approximately the same, but the width very different, the ratios 

 formed by a combination of the length of one with the width of 

 the other are the same as the original ratios. The data of the F3 

 generation clearly point to the action of several factors in 

 producing the difference between the widths of the two leaves. 



The position of the greatest width is a very important 

 point in dealing with the leaf shape. The above diagram 

 shows how the appearance of the leaf can be entirely altered by 

 varying the position of this point. 



