LIFE HISTORIES OF FAMILIAR PLANTS 



marvellous though it may seem, the plant then 

 buries its pods in the ground, and so sets its 

 own seeds. 



It happens that, although the subterranean 

 clover has now only two or three perfect flowers 

 in each head, yet by descent it should have many 

 more, and when the pods begin to ripen, traces of 

 its undeveloped flowers then appear from the 

 centre of the head in the form of several curious, 

 short, five-spined fibres. 



All the five spreading spines on these blunt 

 fibres are the modified remnants of the five lobes 

 of the calyx of one of the abortive flowers of the 

 head ; these now are developing for an entirely 

 different purpose. As the head bends down and 

 comes in contact with the soil, the ripe seed pods 

 bend back close to the head, and thus the spiny 

 fibres lead the way ; slowly they work their way 

 nto the ground like an auger, and in this manner 

 the seed pods are sown, and at the same time 

 protected while the sowing process is taking place. 

 By this modification of its flower-head the subter- 

 ranean clover can afford to dispense with all its 

 flowers but two or three in each head, and can 

 even then better hold its own on the dry and 

 closely-grazed pastures where it is generally found. 

 Its adopted methods of sowing its seeds insure so 

 well the development of the offspring that the 

 abortive flowers are more valuable to the species 

 in their modified form than if they fulfilled their 

 ordinary functions in the flower-head. 



Indeed, this straggling little clover probably 



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