70 BRITISH FLOWERING PLANTS chap. 



surface of the leaf is protected by a covering of wax, 

 and rain falling on it collects in drops. Moreover, the 

 surface of the leaf where it joins the stalk is slightly 

 raised, and the edges are bent up and down in waves. 

 The result is that the raindrops roll away to the edge on 

 the slightest rocking movement. This gives also a peculiar . 

 appearance to the shadow of the leaf, which assumes the 

 form of radiating dark strips with intermediate light 

 bands. The leaves are often purple on the under side 

 from the presence of anthocyan, which, by changing 

 light rays into heat, promotes the work of the leaf. 



The flowers lie on the surface of the water, and are 

 the largest and perhaps the finest of our native flowers. 

 The carpels are embedded in a thick receptacle, radiating 

 from the centre. The flowers open towards the middle 

 of the day, and close in the evening and in wet weather. 

 The anthers open with the flower, or sometimes a day 

 later. They bend over the stigma, and thus in the 

 absence of insects ensure self-fertilisation. The flowers 

 smell of honey, and the stigma exudes a small quantity 

 of fluid, which, however, can hardly be called honey. 



The plant occurs throughout Europe, Northern and 

 Central Asia, and North America. 



NUPHAR 



N. lutea (Yellow Water-lily). — The leaves are of 

 two kinds — floating and leathery, and submerged and 

 membranous. The 5 or 6 yellow sepals are concave and 

 much larger than the petals. The petals and stamens 

 are numerous. The numerous carpels are radiating, fleshy, 

 and united, but separating when ripe ; the stigma has 

 14-20 rays. The flowers have a faint scent resembling 

 brandy. Honey is secreted by the outer surfaces of the 

 petals, and collects in the angle between the petals and 

 sepals. The stigma is ripe when the flowers expand, the 

 anthers a little later, beginning from the outside. The 

 yellow pollen grains are large, ellipsoidal, and rough. The 

 flowers are visited by a few beetles and flies. The geo- 

 graphical range is nearly the same as that of Nymphsea. 



