THE METABOLISM OF PLANTS. 



309 



According to the results of a large number of observers, 

 the daily period in these inflorescences is of this kind, that the 

 maximum excess of temperature is attained during the day 

 and the minimum during the night. The course of the daily 

 periods, as indicated by the occurrence of the maxima, is the 

 less uniform the shorter the grand period. This is clearly 

 seen on comparing the daily periods of inflorescences which 

 have longer or shorter grand periods. Thus in the case of 

 Arum maculatum (see table above) the grand period is rather 

 short, and the daily maximum occurred later in the middle of 

 the grand period than at its beginning or towards its end. 

 In Philodendron bipinftatifidum, in which the grand period 

 extends over only 34 36 hours, Warming observed that the 

 maximum excess of temperature (i8'5C.) occurred on the 

 first day at 7 p.m., and on the second day (5 7 C.) between 



