2 3 - 1 Trelease: Elongation of Banana Leaves 93 



column were then separated into five groups, of ten each, and 

 the average for each group was calculated. The averages are 

 presented in Table 5. Besides the actual averages of the five 

 groups of values, the table also shows the relative values of 

 these averages, each expressed in terms of the uppermost one 

 considered as 100. 



1 diurnal increment, 



Table 5. — Relationships among data represents 

 turnal increment, twenty-four-hour incremei 

 increment to diurnal increment; actual averages are given for each 

 kind of data, and also values relative to the first in each column. 



ss£±ur 



-St- 



_lin Cr e- 



TW rn n c t r y ete U n r t h ° Ur 



Ra &ir 



AM 



Relative 



Actual. 



Relative 



Actual. 



Relate 



Actual. 





Highest ten » 



£ 



z 



Fs 



■ 



F« 



Z 



K 



«J 







L " w "" e ° b 



16 



6 99 



» Really the highest 9 ; see Table 1. * Really the lowest 9 ; Bee Table 1. 



From Table 5 it is at once seen that progressively lower 

 values of the day increment correspond to correspondingly lower 

 values of the night increment and also of the twenty-four-hour 

 increment. On the other hand, progressively lower values of 

 the day increment correspond to progressively higher values of 

 the night-day ratio. The range is greater and the differences 

 are greater for the day increment than for the night increment. 

 In a general way, night increments and twenty-four-hour incre- 

 ments vary directly with day increments, while ratios vary 

 inversely with day increments. An explanation of the inverse 

 relationship between the ratio values and the values for each 

 of the three increments lies in the fact that the change in day 

 increments is much more pronounced than the change in night 

 increments, which remain relatively constant. The same ap- 

 proximate relationships suggested by the arrangement of all the 

 data in the series just described are brought out by an exami- 

 nation of the records of the individual plants, showing the 

 fluctuations from period to period in the rates of elongation. 



LEAF POSITION 



The two halves, right and left wings, of the banana leaf lie 

 in nearly the same plane at night, like the right and left halves 



