THE VEGETABLE KINGDOM. 471 



lilies (Nymphcea alba, Linn.) which ornament our ponds so 

 splendidly with their virgin corollas. When the plant 

 grows at the edge and is quite dry, its peduncles are only 

 an inch or two long; whilst, when it is planted in deep 

 water, these organs stretch out three or four feet, in order 

 that the flowers may expand upon the surface of the wave. 



When incapable of executing such manoeuvres, these 

 plants make use of some equivalent proceeding instead. 

 This was observed by Ramond in a Water Ranunculus 

 (water crow-foot, or Ranunculus aquatilis, Linn.) which he 

 met with in the Pyrenees. Placed in deep water, and not 

 being able to bring its flowers into contact with the atmos- 

 phere, the plant supplied this want by an ingenious means. 

 Each corolla had secreted a large bubble of air, which en- 

 tirely enveloped it in such a manner that, though beneath 

 the water, fecundation was accomplished just as if the floral 

 apparatus had not been submerged at all. 



But of all plants the fecundation of the Vallisneria spi- 

 ralis has acquired the most celebrity. This dioecious plant 

 lives in the rivers of the south of France. Its female 

 flowers, attached to peduncles twisted spirally, expand upon 

 the surface of the water, all the movements of which they 

 follow. Like a spring, their spiral lengthens when the 

 water rises, and shortens when it falls. The male flowers, 

 not being provided with this elastic apparatus, find them- 

 selves chained to the foot of the plant at the bottom of the 

 water. How are the wedded pair to become. united? Na- 

 ture has foreseen all. When the moment has arrived the 

 peduncles of the male flowers break ; these mount to the 

 surface of the water, spread out and form a numerous cor- 



