196 STUDIES TN INDIAN SUGAROANES 



aud ascends more rapidly. The inaxiniuin is reached in 15 joijits in Saretlia, 

 against 21 joints in Sunnabile, and is 9" greater. A comparison, however, of the 

 lamina curve with th( se of joint aud sheath, shows certain fundamental differ- 

 ences. With steep rise and fail the lamina curve remains more or less horizontal 

 at the top and thus presents a generally flattened appearance, which appears to 

 be characteristic of all mature lamina curves. Once the region of full grown 

 leaves is reached, there is little variation in length from joint to joint, renderii\g 

 difficult all attempts at finding correlations between the lengths of leaves and 

 other organs in different parts of the canes. In both the joint and sheath curves, 

 on the contrary, the rise is very rapid at first and, once the maximum has been 

 reached, a continuous descent follows. The sheaths and joints are longest 

 in the young cane and become continuously shorter as growth proceeds. 



A study of the 1917 crop, in which a considerably larger number of varie- 

 ties were studied in each group, bears these remarks out. But, as in the case 

 of joint and sheath, the effect of immaturity and poorer growth is shown, and 

 the curves are much lower and shorter and, so to speak, cut off in the middle, 

 because of the fewness of organs developed. The following are the measurements 



obtained : — - 



Average length of successive laminas, 1917, nine months old, in inches: 



Saretha group. 29, 33, 37, 4.1, 45, 48, 49, 51, 51, 52, 52, 53, 53, 52, 52, 

 52, 51, 50, 49, 49, 50, 51, 50, 49, 47, 43, 37, 29, 21. 



Sunnabile group. 28, 34, 37, 40, 42, 44, 46, 46, 47, 47, 47, 48, 47, 47, 

 46, 46, 45, 44, 44, 44, 45, 45, 45, 44, 44, 42, 39, 32, 

 21, 18. 



(7) Average length oj mature lamina. This was obtained from the above 

 two series, leaving out the last 8 as possibly immature. The lengths in 1916 

 were, for Saretha 4' 5" and for Sunnabile 3' 9", and in 1917 Saretha 4' 0" and 

 Sunnabile 3' 8". The leaves in the Saretha series are distinctly longer. A 

 reference to the curves will show that it is possible that the lower figures in the 

 nine months curves may be due to the fact that the longest had yet to come 

 when the canes were measured. The maxima in lamina curves are considerably 

 later than in joint and sheath curves, and the shortness of lamina in 1917 may 

 not therefore be due entirely to poorer growth. The Mesangan section consists 

 of much larger cane varieties than the Katha, and this is reflected in the length 

 of lamina. In 1917 the average in the Katha section was 3' 10" and that of 

 the Mesangan 4'2", so that in this respect the intermediate nature of the latter 

 section between the Katha section and the Sunnabile series cannot be gauged 

 by mere length in inches. 



