ACTIVE LIVING CELLS 



273 



Tries. 



ordinary parenchyma cell. D, sieve plate and companion cell 

 as seen in cross-section. E, epidermal cell with large vacuole. 

 but. large conspicuous nucleus in contact with local thickening 

 of outer cell wall which is being formed ; p, pit in lateral wall. 

 F, large water bladder representing a single much swollen cell 

 of the epidermis, with little cytoplasm but large nucleus ; ep., 

 ordinary epidermal cells ; mes., mesophyll. 



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