C. A. BARBER I4l 



the first glance it is natural to assume that, in this leaf width, carrying with 

 it greater assimilative power, there may be a difference in the ultimate value 

 of the seedling and the quality of its juice. And this suggestion receives 

 support in that the indigenous Indian canes are, as a whole, characterized 

 by extremely narrow leaves as contrasted with canes grown in the tropics. 

 Thus, the width of a leaf in the Chin group might be anything from 

 0-6" — 1'3", in the Pansahi group from I'D" — 2-0" and in exotic canes from 

 2-0"— 4-0". 



Considerable attention has accordingly been paid to leaf width in the 

 seedlings examined. It nnist be conceded that there is a great deal of 

 variation in the width of the leaves of each individual seedling, dependent 

 on the vigour of growth and the age and position of the leaf on the 

 stem. In order to obtain a common basis, it was decided to measure 

 the widest leaves observable. All the seedlings are thus measured _ at 

 crop time, ten shoots being taken and the widest in each measured 

 and an average struck. This has given on the whole satisfactory 

 results, and ordinary variation curves have been obtained for each 

 set of seedlings. That for 360 Karxn seedlings is appended below. But 

 it has been found that this method is unsafe if applied to young and grow- 

 ing plants. In a batch of half grown Karun seedlings (1912-14), 236 in 

 number, this method of averaging the widest leaf was adopted, but the classes 

 resulting, when compared with those obtained in the same seedlings at crop 

 time, showed many serious discrepancies, and this has led to a study of the 

 leaf width of sugarcane plants at different periods of growth. In a growing 

 shoot it was observed that, for a considerable period, each new leaf was on 

 the average wider than its predecessor and thus, in seeking the widest leaf, 

 this was usually found near the apex of the shoot. It is obvious therefore 

 that the leaf width of any seedling, judged by this method, will be influenced 

 by its relative vigour of growtli as compared witli its neighbours. The more 

 rapidly growing seedling will obtain a higher place in leaf width than is 

 justified by its ultimate development. It has not yet been ascertained at 

 what stage the maximum leaf width is reached, but experimental measure- 

 ments are being made with a set of j)lants to determine this. It has been 

 assumed that, in fully matured plants with healthy leafy shoots, this 

 error is eliminated, although it is possible that, by this time, a converse 

 diminution of leaf width may have set in. 



The accompanying table gives the leaf widths of the 1912-14 seedlings 

 with approximate figures for their parents. 



