174 



AERENCHYMA 



Other examples of adaptation to the habitat-conditions in 

 aquatics are: restriction of the stomata to the upper surface 

 of floating leaves, development of a covering of wax on the 



E.J.S. 



FIG. 91. Transverse section of the vascular strand of the Floating Pond- 

 weed (Potamogeton natans}. C., xylem-canals ; E., endodermis ; 

 /., air-canal ; P., sieve-tube. 



latter, and the aerenchyma encountered in certain marsh-plants 

 (e.g. Purple Loosestrife, Ly thrum salicaria ; Gipsy wort, Lycopus 

 europaus ; Hairy Willow-herb, Epilobium hirsutum). Aeren- 



