IOO 



HOUSE, GARDEN, AND FIELD 



Nuphar, the yellow water-lily, in addition to its floating 

 leaves, which nearly resemble those of Nymphaea, has 

 submerged leaves, which are thin, like many other sub- 

 merged leaves, and wavy. Their large size and abundant 

 chlorophyll shows that they are functional, and their 

 presence in Nuphar as well as their absence in Nymphsea 

 is easily explained by the situations in which each kind 

 of water-lily is most at home. Nuphar flourishes best in 



shallow pools, where the 

 sun's rays can reach the 

 bottom ; Nymphaea prefers 

 a depth of twenty feet or 

 more, where the bottom 

 must be practically dark. 

 In the colder months of 

 the year, when the floating 

 leaves have not yet made 

 their way to the surface 

 or are turning yellow with 

 age, the submerged leaves 

 of Nuphar are probably a 

 valuable source of assimi- 

 lated carbon. 



The flowers of Nuphar 

 differ materially from those 

 of Nymphaea. They do 

 not float, but stick out of the water, and expand in 

 the air, not sinking by night. There are more outer 

 leaves than in Nymphaea, the petals are smaller, the 

 carpels not sunk in the flower-stalk. The flowers exhale 

 a peculiar alcoholic odour, which is perhaps attractive 

 to the beetles, flies and bees which visit them. The 

 fruits do not sink like those of Nymphaea, but float. After 

 a time the green rind absorbs water until it swells and 

 bursts, exposing the white carpels, which have the arrange- 

 ment and appearance of the segments of an orange (Figs. 

 27, 28). The carpels soon break loose and float on the 



FIG. 28. Yellow water-lily. Fruit 

 burst open and exposing the carpels. 

 Slightly reduced. An enlarged seed is 

 shown at the side. 



