72 TALKS AFIELD. 



Fig. 63. If we were to make a cross-section 

 of a leaf, cutting across the leaf from the 



Fig. 63. Fig. 64. 



upper surface to the lower, and were to ex- 

 amine the section with a microscope, an 

 arrangement something like that in Fig. 64 

 would be presented. On the upper surface 

 are to be seen the flattened epidermal cells, 

 while immediately beneath them are two 

 rows of long palisade cells. The under sur- 

 face is also faced with the flattened cells. 

 The lower half of the 

 interior of the leaf is 

 made up of a loose ag- 

 gregation of irregular 

 cells, between which 

 are air spaces. If, 



Fig. 65. .J. 



now, we magniiy a 

 portion of the under surface of the leaf w^e 

 discover many crescent-shaped cells lying 

 face to face, with an opening between them. 



