DIV. I 



MORPHOLOGY 



173 



tissue consists of large colourless cells containing a large vacuole. Every 



epidermal cell may be regarded 



as storing water. In some cases, 



however, the epidermal cells attain 



a huge size and constitute a large 



proportion of the leaf, or they 



may be divided parallel to the 



FIG. 196. Twig of Ruscus aculeatus. /, 

 Leaf; d, cladode ; W, flower. (Nat. 

 size. After SCHENCK.) 



Fin. 195. Salicomia herlacea, a character- 

 istic halophyte. (From SCHIMPER'S 

 Pla nt- Geography. ) 



FIG. 107. Opuntla manacantha, Haw., showing 

 flower and fruit. (J nat. size. After 

 SCHUMANN.) 



upper surface and give rise to a many-layered water tissue (various 



