502 THE UNIVERSE. 



respect. The task itself seems to be chiefly intrusted to 

 the peduncle. In some plants growing in the depths of 

 our marshes this support lengthens out, even to an immense 

 extent if necessary, so as to raise the flower above the 

 surface of the water. This is frequently seen in the 

 magnificent water-lilies {Nymplicea alba, Linn.) which orna- 

 ment 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 tAvo long ; Avhilst, 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 manoeuATCS, these 

 plants make use of some equivalent proceeding instead. 

 This was observed by Ramond in a Water Eanunculus 

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

 he met with in the Pyrenees. Placed in deep Avater, 

 and not being able to bring its flowers into contact Avith 

 the atmosphere, the Avant of this Avas supplied by an in- 

 genious means. Each corolla had secreted a large bubble 

 of air, AA'hich entirely enveloped it in such a manner that, 

 though beneath the Avater, fecundation Avas accomplished 

 just as if the floral apparatus had not been submerged 

 at all. 



But of all plants the fecundation of the Vallisneria 

 S2nralis has acquired the most celebrity. This dioecious 

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

 female floAvers, attached to peduncles tAvisted spii^ally, 

 expand upon the surface of the Avater, all the move- 

 ments of Avhich they folloAV. Like a spring, their spiral 

 lengthens Avhen the Avater rises, and shortens Avhen it 

 falls. The male flowers, not being provided Avith this 

 elastic apparatus, find themselves chained to the foot of 



