62 



STUDIES IN INDIAN TOBACCOS. 



Table VII. 



Average Number of Leaves in the Types of iV. tabacmn. 



leaves. Enumeration at the base, where the scars are close 

 together,-js facilitated by marking the point of commencement 

 with a knife, and each subsequent scar by sticking into it the 

 point of a lead pencil. Care is necessary not to mistake con- 

 tractions in the main root for leaf scars, but with a little practice 

 this can be done fairly easily, except in the case of a few types. 

 The determination of the last leaf on the axis is more diffi- 

 cult. In many types of tobacco, the leaves at the top of the 

 stem are carried up the branches they subtend and therefore 

 do not appear to be on the main stem. In such cases, however, 

 there is generally a faint line running from the leaf down to the 

 main stem. The method of enumeration adopted in ^tliese 

 investigations has an advantage over previous methods used in 

 titat it represents the true physiological activity of the plant 

 and not an arbitrary number. 



As regards the effect of environment on the numberof leaves, 

 no special investigations have been undertaken, but the fact 

 that the average value of this character and the range of varia- 

 tion in the parent forms is practically constant in different 

 years, would indicate that changes in a normal environment have 

 little effect. This agrees with the conclusion of Hayes that 

 the number of leaves per plant was little affected, unless the 



