OFFICE OF STOMATA 



173 



often found per square inch on the under side of the 

 leaves of ordinary cultivated plants. The stomata 



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A -' C 



Fig. 41. Diagram of open and partly closed breathing-pores on leaves. 

 Through these openings water escapes from the plant. (From King's 

 " Irrigation and Drainage.") 



or breathing-pores are so constructed that they may 

 open and close very 

 readily. In wilted 

 leaves they are prac- 

 tically closed ; often 

 they also close im- 

 mediately after a 

 rain; but in strong 

 sunlight they are 

 usually wide open. 

 It is through the 

 stomata that the 

 gases of the air enter 

 the plant through 

 which the discarded 

 oxygen returns to the atmosphere. 



It is also through the stomata that the water which 



Fio. 42. 



Photograph of stomata or breath- 

 ;-pores on under side of leaf. 



