CHAP. I.] 



PL4NT ARCHITECTURE. 



39 



forceps and examined in water under the microscope, 

 the origin and development of the stomata may be easily- 

 followed. 



The cells of the epidermis as seen from the surface 

 are brick-shaped, their long diameter being arranged in 

 the direction of the length of the leaf. The stomata 

 originate as follows. A certain epidermal cell is divided 



.sp -- 



Fig. II. A fragment of epidermis from the under surface of a leaf 

 ol EtumyrMis japonica, showing four stomata; sp, guard-cells of the 

 stoma. (Highly magnified. ) 



into two parts by a wall that is always formed at right 

 angles to the length of the leaf. One of the small, or 

 daughter-cells thus formed, undergoes no further de- 

 velopment, but loses its protoplasm, becomes cuticularized, 

 and forms an ordinary epidermal cell ; the other daughter- 

 cell, that is, the other half of the epidermal cell, now 

 called the mother-cell of the stoma, retains its protoplasm 



