i68 FREAKS OF PLANT LIFE. 



flexible, and that they arise from flexible branches, it 

 is incredible that an object as blunt as one of these 

 flower-heads could penetrate the ground by means of 

 the growing force of the peduncle, unless it were 

 aided by the rocking movement. After a flower-head 

 has penetrated the ground to a small depth, another 

 and efficient agency comes into play ; the central 

 rigid aborted flowers, each terminating in five long 

 claws, curve up towards the peduncle, and in doing 

 so can hardly fail to drag the head down to a greater 

 depth, aided as this action is by the circumnutating 

 movement, which continues after the flower-head has 

 completely buried itself The aborted flowers thus act 

 something like the hands of a mole, which force the 

 earth backwards and the body forwards." ^ 



Another instance, equally remarkable, is that of the 

 "ground-nut," or "ground-pea" {AracJiis hypogcBO) 

 which is cultivated in all tropical countries. After 

 the flowers fall the stalk of the ovary elongates itself 

 considerably, bends downwards, and the ovary is 

 buried in the ground, where the pod is matured. It 

 is said that flowers which grow too high on the plant 

 to reach and bury themselves in the ground, do not 

 produce seeds. The same phenomenon of rotation 

 or oscillation is plainly visible in the ovaries directed 

 towards the ground as in the previous example. Any 



* Darwin, " Movements of Plants," p. 514. 



