86 TALKS AFIELD. 



uous flowers, which are collected in a tightly 

 covered ball and borne on short stalks far 

 under water, as seen in A in Fig. 69. When 

 the little flowers are about full-grown the 

 covering of the ball breaks open, splits into 

 three parts, and each flower, securely wrapped 

 up in its sepals, separates itself from its 

 stemlets and rises to the surface of the water. 

 When upon the surface its three sepals open 

 and the anthers mature. The pollen is dis- 

 charged upon the water and is carried by 

 the currents to the clove-like female flowers 

 which have raised themselves on long stalks 

 to reach the surface (^). The three broad 

 stigmas receive the pollen, the ovules are 

 impregnated, and then the long stalk coils 

 up and draws the fruit under water to ripen. 

 This curious plant bears a name which does 

 honor to A. Vallisneri, an early Italian bot- 

 anist, and which records the phenomenon of 

 the spiral contraction of the flower-stalk : it 

 is known as Vallisneria spiralis. 



The most peculiar adaptations for cross- 

 fertilization are those which attract insects 

 and other animals, and which make the in- 

 sect to be an unconscious but an indispensa- 

 ble aid to the plant. Delpino calls these " in- 

 sect loving " plants entomoj)hilous. There 



