WATER-LILIES 



97 



two at its base and an inch or two at its tip. Branched 

 rootstocks are often found. The rootstock contains so 

 much air that it floats in water when the roots are severed. 

 So far the description applies both to Nymphaea and to 

 Nuphar. 



The rootstock of Nymphaea (white water-lily) is black 

 externally, and roughened by the very numerous leaf- 

 scars, which are prominent, smaller than in 

 Nuphar, and set much more closely. The 



FIG. 23. Root 

 of yellow water- 

 lily. 



FIG. 22. White water-lily. Part of upper 

 surface of rootstock (natural size), showing 

 the bases of old leaves, with air-canals. 



arrangement is quincuncial (*****). When 

 preserved in a watery fluid, both the root- 

 stock and the water in which it is immersed 

 turn to an inky black, which is due to tannin present 

 in large quantity in the tissues. When cut across, the 

 rootstock of Nymphaea shows a central zone of harder 

 tissue ; the vessels are few and scattered. 



The rootstock of Nuphar is not so dark as that of 

 Nymphaea, but of a stone-colour blended with green. 

 The leaf -scars are larger and more distant from one 



