52 STUDIES IX INDIAN TOBACCOS. 



other hand, given rise only to late plants. The difference 

 between the cultures derived from 738 and 694 was most marked 

 in the plot. There is a good deal of difference between the 

 individual cultures of 694. No. 694-1 has a maximum flowering 

 period between the two parents, while 23 and 38 are much later 

 than Type 51, the late parent. It is impossible to say whether 

 a culture is pure as regards its time of flowering until it has been 

 proved impossible to produce from it by selection cultures 

 differing in this character, but 738-19 and 738-81 may possibly 

 prove constant, as may also some of the cultures of 694. 



If we consider the F^ cultures as a whole, we find a very 

 distinct separation as regards the flowering period. In addition, 

 Avhile one culture has been isolated, which is slightly earlier 

 than the early parent, there are several which are decidedly 

 later than T3^pe 51, the late parent. The range of the earliest 

 flowering culture does not overlap that of the latest. 



Tables II and III show the same general results for other 

 crosses, but the separation between the cultures is not so great, 

 as the flowering period of the parents is not ver}^ different in 

 either case. The extremes in the F., are represented in the cross 

 Type 16 and Type 35 (Table II) by cultures 27 and 200, and in 

 cross Type 23 ;< Type 38 by cultures 104 and 9. In all three 

 the two parents in successive years bear a similar relation to 

 one another. 



2. HEIGHT. 



The height was measured from the point where the roots 

 begin to the apex of the stem, which in N. tahacum ends in a 

 capsule. Three or four flowering branches arise round this 

 point and help to define it, but there is no difficulty in seeing 

 either the capsule or its scar at any period in the life of the mature 

 plant. In order to count the lower leaves, the plants were up- 

 rooted and the determinations of the height and the number of 

 leaves were made simultaneously. The height was measured 



