372 



LESSOJrS WITS PLANTS 



\ 



Fig. 392, 



the fruit to the point 

 a. Inside this tube 

 is the plumule. The 

 hypocotyl continues 

 to elongate, becoming 

 thick and heavy at its lower end. 

 When six inches or a foot long, it 

 breaks away from the joint a, carry- 

 ing the liberated plumule with it, and 

 strikes root- end down in the mud. 

 Roots push out from the lower end, 

 and the epicotyl rapidly elongates and 

 rears itself above the water. 



467. A piece of a mangrove branch 

 is shown natural size in Fig. 393. An 

 aerial root is pushing through the 

 thick bark. 



468. The root makes a strong 



curve when it strikes oflE the 



branch, and then grows directly • 



downward towards the water. 



The branch from which it springs 



may be only a few inches above 



the water, or it may be ten 



feet ; but the root pushes 



on until it inserts itself in 



the mud, and there makes 



The hypocotyl nearly full grown, a rOOt Systcm of itS OWU. 



