96 



A MONTANE EAIN-FOEEST. 



shows a maximum of the daily relative transpiration at 10 a. m., the 

 maximum for evaporation and transpiration at 12 noon, and the maxi- 

 mum of stomatal aperture at 2 p. m. Between 10 and 12 a. m. there 

 was a pronounced increase in the stomatal openness, which was accom- 



FiG. 17. — Ciirves for simultaneous experiments with Peperomia turfosa (upper) and Pilea nigres- 

 cens (lower) which determination was made of transpiration (T), relative transpiration 

 (— ), stomatal area (S),and evaporation (77, ). 



panied by a plateau in the curve of relative transpiration. Between 

 12 and 2 p. m. there was a considerable fall in the relative rate at the 

 same time that the stomatal aperture was still increasing. The curves 

 for Pilea show a general similarity to those for Peperomia: there is the 



