80 



A MONTANE RAIN-FOREST. 



transpiration. This was done in the following manner: The relative 

 rates for the three plants exhibited in tables 23, 24, and 25 were grouped 

 according to the rates of evaporation which prevailed during the same 

 hours for which the relative rates were determined, and were grouped 

 by increments of 1 milligram per square centimeter of water surface 



TABLE 29. Averaged daily march of relative transpiration in three species, together with 



maximum and minimum readings. 



Averaged from 82 readings for Peperomia turfosa, 84 for Pilea 

 nigrcscens, and 56 for Diplazium cettidi folium. 



.189 

 .160 

 .140 

 .120 

 .100 

 .080 

 .060 

 .040 

 0.20 



D.c. 



NIGHT 



8-9 A. M. 



10-11 12-1 P." 



4-o 



6-7 



8-9 



FIG. 11. Mean daily course of relative transpiration rate for Diplazium, Pilea, 

 and Peperomia turfosa, as averaged from graphs given in figs. 8, 9, and 10. 



per hour. The averaged relative rates were then plotted to evapora- 

 tion. The resulting curves show the collective behavior of the several 

 plants experimented upon, in the several series in which they were run. 

 On account of the many fluctuations of the curves they were smoothed 

 in groups of three, the average of each three readings being taken as 

 the value of the middle one of the three. The smoothed curves are 

 given as dotted lines in figure 12. Pilea shows a fall in relative rate 

 which is irregular but progressive ; Peperomia shows a remarkable rise, 



