40 



TRANSPIRATION IN A DESERT PERENNIAL. 



-4.8 

 -4.0 

 3.2 

 -2.4 

 -1.6 

 - .8 



VI xw 



\v 



Farkinsonia 



Picric 

 Alcohol 



Picric 

 Alcohol 



5.6 

 h4.8 

 4.0 

 3.2 

 -2.4 

 -1.6 

 - .8 



VTxw 



9 10 11 12 1 2 3 4 5 6 7 f< 9 



Fig. 19. Comparison of picric-acid method forstomatal measurement with the absolute 



alcohol method. 



10 11 12 1 



Fig. 20. Graphs for stomatal openings and relative tran.s- 

 piration. Exps. XIV, XVI, XVII. 



