TEANSPIEATION BEHAVIOR OP RAIN-FOREST PLANTS. 97 



daily maximum of transpiration and evaporation at 12 noon, with a 

 plateau in the curve of relative transpiration between 10 a. m. and 

 2 p. m., accompanied by a sharp rise in the curve of stomatal openness 

 between 10 a. m. and 12 noon, and a less rise between 12 and 2 p. m. 



Fig. 18. — Curves for simultaneous experiments with Diplazium celtidifoUum (upper) 

 and Asplenium alatum (lower). These experiments were carried out on the same 

 day as those with Peperomia and Pilea (fig. 17). The curves are: transpiration (T), 



(E\ . /T\ 



— ), relative transpiration (:£;), and stomatal area (S). 

 10' ^Hj 



In the afternoon, between 4 and 6 o'clock, there is a rapid fall in the 

 relative rate, with no accompanying change in the stomatal openness; 

 between 6 and 9 p. m., however, the two rise in company. 



The daily march of stomatal openness for Diplazium is extremely 

 uniform. The transpiration of the plant followed the evaporation 



