FERTILIZATION IN PIMA COTTON 



17 



!>. the probable error having been computed from the departures of 

 the daily means of 20 flowers from the mean of the daily means. 

 The half-hour means for the day when the opening was most rapid 



S &JO 700 730 S.OO S.30 S.OO S.JO /GOO /O30 



T/AfFJ 0/=~ 03S£ftM7Y0/V fa.A/J 



Fig. 2. — Average, maximum, and minimum rates of expansion of the corolla of Pima 

 cotton, as indicated by the mean aperture of the corolla at half-hour intervals during 

 the morning, this having been determined by measurement of 20 flowers on each of 

 15 days during the period from July 29 to September 15, 1919. The mean hour of 

 sunrise during this period was 5.26. The dotted and broken lines indicate the rates 

 on the days when expansion was most rapid and least rapid, respectively, and the solid 

 line indicates the average rate of expansion for all 15 days. 



and for the day when it was least rapid are also given in the table. 

 The average, maximum, and minimum rates of expansion are shown 

 graphically in Figure 2. 



22421—23 3 



