SEED-BEARIXG PLANTS 445 



If one digs up a bulb in the fall, he wiU find the flower 

 perfectly formed, and ready to be raised above the ground 

 the following spring. All the parts of the flower, at this 

 period, are white, on account of having been formed in 

 entire darkness; and they are also quite brittle. 



When the buds resume .their growth the second spring 

 they push up through the ground quickly, and with con- 

 siderable force. The pointed end of the sprout is covered 

 by a mass of hard tissue, which protects the more delicate 

 cells below from injury. The well-protected tip, and the 

 growth-force, enable the sprout to pierce even small 

 twigs. This has given rise to the striking name of "vege- 

 table awl." 



As soon as the sprout is well above the surface of the 

 ground the flower bud becomes free from the parts that 

 enclose it, and expands into the nodding blossom; pollina- 

 tion is accomplished, and the life-cycle begins again. 



The life cycle of another angiosperm, the water-plantain 

 {Alisma Plantago-aquatica) , is indicated in Fig. 329. 



