558 



ECOLOGY 



Fig. 800. — A cross section through a 

 stoma from a leaf of the carnation (Dianthus 

 CaryophyUus) ; by reason of the heavy cu- 

 tinization of the outer epidermal wall (w), 

 the stoma Ues below the surface level of the 

 leaf; note the thin places Qi) above and 

 below the dorsal wall {d) of the guard cell 

 fe)> representing the so-called hinges which 

 are thought to facilitate guard-cell move- 

 ment; the chamber above the stoma is 

 called a stomatal pit; general lettering as 

 in fig. 79s ; highly magnified. 



Fig. 802. — A cross sec- 

 tion through a stoma from 

 the under leaf surface of the 

 nipa palm (Nipa fruticans), 

 showing the tortuous pas- 

 sageway (sj), which must 

 be traversed by transpiring 

 water that passes from the 

 stomatal cavity (c) to the 

 exterior at e; g, guard cell; 

 highly magnified. — From 



BOBISUT. 



Fig. 801. — A cross section through a stoma from a leaf of the India-rubber tree 

 (Ficvs dastica) ; the stoma lies below the surface level of the leaf by reason of its position 

 beneath the subsidiary cells (J), which have projecting ridges (;•') partially enclosing the 

 pit (/>); the dorsal wall (d) of the guard cell is so braced by the thick walls of the ad- 

 joining cells that guard-cell movement must be sUght; note that the epidermis (e) con- 

 sists of three cell layers and that the cuticle (z) is highly developed; general lettering 

 as in Fig. 795; highly magnified. 



