Sa)iipsoii Olid Allot : niYSiCAL factors on transpiration. 45 



Comparative Transpiration of Polydemic Forms. 



In order to correlate a relation between the behavior of poly- 

 demic forms, that is, plants growing in two or more habitats (see 

 Fig. 5), as found near Minnehaha, Colorado, plants of both forms 

 were set up in potometers and stationed in both sunny and shady 

 habitats. As far as possible, sunny days were chosen for the obser- 

 vations, weighings being made twice daily as in previous experi- 

 ments. 



The results are as follows : 



PHYSICAL FACTORS— 



Light .6 



Temperature 63.5% 



Humidity 52% 



TABLE V. 

 SERIES I. Sunny Habitat. 



Day Loss Night Loss stomata Size of opening in 



per sq. per sq. No. per sq. cm. 



No. cm. in cm. in Above Below Above Below 



mg. mg. 



Plant 



