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A TEXTBOOK OF THEORETICAL BOTANY 



move easily through the epidermis from cell to cell, and it constitutes a first 

 reserve from which water can be quickly mobilized to supply any area 



Tabular epidermis 



Sclerenchyma 



Fig. 443. — Lysimachia punctata. Tabular epidermal 

 cells in stem. 



threatened by excessive evaporation. The lateral walls are also sometimes 

 remarkably convoluted, as seen from above, forming a complex system of 

 dovetailing whereby the cells are closely knit together (Fig. 444). The 



/'»/A' 







Fig. 444. — Carex pendula. Superficial view of 

 epidermal cells of leaf. 



primary requirements of toughness and flexibility are thus ensured. This 

 unique structure is probably due to rapid lateral expansion of the cells at a 

 time when their outer walls are more rigid than their lateral walls. 



