50 



Principles of Plant Culture. 



65. Stomata (stom'-a-ta). Minute openings through 

 the epidermis occur in the leaves and young sterna of 



cf land plants, 



/' connecting 



inter cellular 

 spaces (I, 

 Pig. 17) with 

 the external 

 air. These 

 openings are 

 each bounded 

 by a pair of 

 guar d-cells, 

 called stom- 

 ata, (singu- 

 lar, stoma 



(sto'-ma). Figs. 18 and 19, St). They are chiefly found 

 on the lower side of leaves, and are extremely numer- 

 ous, but are too small ^ ^^ 

 to be seen without the ^ ^^X^^_J^-^'/ 

 microscope. An aver- .. .' // //" A\ W ^ J^ 

 age apple leaf has 

 been computed to 

 contain about 150,000 

 stomata to the square 

 inch on its lower 

 surface. These cells, 

 which are attached 

 together only at their ends and are thickened on their 

 inner side, and become ben t or crescent-shaped when 



Fig. is. Sbowing stomata (st.) on leaf o£ tbe 

 garden beet. Moderately magnified. (After Frank 

 and Tschirch.) See also Figs. 15, 19 and 22. 



Fig. 19. Showing stomata (st.) on leaf 

 of Oldenburgh apple. Highly magnified. 



