42 TILLERING IN INDIAN SUGARCANES 



from other groups and some thick canes and wild Saccharums. Altogether 51 

 clumps containing 133 plants were dissected during this season. The results 

 of this work, briefly alluded to in Memoir III (pp. 156-160), were so sugges- 

 tive and interesting that a fuller series was projected for the 1917-18 season. 

 Six varieties of each of the five classes of Indian canes were chosen ; to these 

 were added six from the unclassified list, six thick cane varieties, the four 

 wild Saccharums growing on the farm and six Madras seedlings, all of which 

 were grown from sets. Owing to the poor growth of the thick canes, a further 

 set of 24 stools were examined at the sugarcane plantation at Nellikuppam, 

 these being all of the Red Mauritius variety, which was known to grow very 

 well there under crop conditions. During this season 239 clumps, consisting 

 of 629 plants, were dissected. The facts observed during the previous year 

 were utilized for the preparation of a definite scheme of observations and 

 measurements, the main purpose of which was the comparison of the branching 

 systems of the different groups and the characters of the branches of different 

 orders. In each plant dissected a diagram was prepared, in which the relative 

 position of the branches was shown, and a formula was prepared, in algebraical 

 form, of the constitution of the plant as far as matured canes were concerned. 

 Besides this, all the canes were measured as to thickness and leng-fch of joints, 

 and notes on runners, curvatures, injuries, etc., were recorded. The present 

 paper seeks to extract the general principles of the branching of the sugarcane 

 plant from this mass of material. 



The following are briefly the results of this study. From the four months' 

 dissections it is seen that the different varieties vary greatly in the rate of 

 maturing and cane-formation, but this study is complicated by the fact that 

 it was impossible to examine all the stools at the same time owing to the large 

 number dissected, the time occupied in the work extending over six weeks. 

 A series of tables have been prepared, from which it is not difficult to judge 

 of the relative rate of maturing of the different varieties {cf. pp. 129-132a). 



From the general formulae of canes at harvest, obtained by averaging 

 the dissections of all the plants of a variety, it is seen that the branching in 

 the various groups, from the wild Saccharums to the thick tropical canes, 

 is of the same nature, but of very different degree {cf. p. 116). Taking a to 

 represent the main shoot, h its branches, c branches of h, that is of the second 

 order, and so on, we get a series of formulae of the canes at crop time, varying 

 from a -f m& + c in the thick canes, to a + m6 •\- \\c •{■ nd + vne ■\- f in the wild 

 Saccharu-ms, and the different groups of Indian canes can be arranged in a 

 series between these two extremes. It is hoped that a study of these formulae 



