INTERNAL TEMPERATURE OF LEAVES. 



241 



Table IX.— January 27, 1906. 



Variegated (green and white) leaf of Acalypha tricolor. 

 (A thin leaf which soon wilts in direct sunlight.) 



In Table VII. (first part) and in Table VIII. the gradual 

 increase of intensity of the sun's radiation is well seen. 

 Although no black bulb thermometer was used, the gradual 

 increase of intensity of radiation is reflected to some extent 

 in the gradual rise of shade temperature of the air. Parallel 

 with this is the gradual rise of temperature of the leaf, e.g., 

 January 25 air temperature rises 25 '5 to 27*5, while the leaf 

 temperature rises 37*2 to 42*0. 



Table X.— November 14, 1906. 



Amherstia nohilis. — Mature leaf, intermediate in thickness 

 between Magnolia sphenscarpa and Acalypha tricolor. 



Time . . 

 Conditions 



Zero 



Deflection 



Water junction tem- 

 perature 

 Shade air temperature 

 Leaf temperature 



10.44 A.M. 



Full sun 



still air 



00 



2-9 



27' 

 26- 

 42 



10.55 A.M. 

 Full sun 

 still air 



0-0 



30 



27-8 

 27-2 



42-8 



10.4 A.M. 



Full sun ; 



still air 

 00 

 30 to 3-2 



26-8 

 26-4, Nov. 15 

 41-8 to 42-8 



Table XI.— December 14, 1906. 

 Mature leaf of Saraca indica. 



