56 



DICOTYLEDONS 



arrow and remains there up- 

 right, the side-roots growing 

 quickly and fixing the tender 

 plant in the unsettled soil. 

 Thus the tender shoot which 

 unfolds its leaves soon after, 

 is kept ahove the water. 



5. Breathing of the roots. — 

 Every growing part of a plant 

 requires the oxygen of the 

 air to sustain its life. So 

 also the root of the Mangrove 

 tree. But the muddy soil is 

 destitute of oxygen which is 

 used up in the process of de- 

 composing the vegetable sub- 

 stances lying there. Other 

 plants that have to live under 

 similar conditions such as the 

 Lotus (page 3) supply their 

 roots with air by channels 



Fig. 58. 



Breathing roots 



of Manjrrove. 



Fig. .")9.- Hraiicli of a Mfttigrovn trc*^ (lininuicra) 

 with fruits. On tlic lol't side tiio tiower of it. 



extending from the leaf 

 blades to the extremest 

 points of the root. But 

 such a system of 

 channels in the stem 

 would not do in tlie 

 case of a tree like the 

 Mangrove, a.s it Avould 

 lessen the mechanical 

 strength of such a tall 

 tree witli its branches. 

 How, then, can the 

 roots of the Mangrove 

 tree breathe? They 

 simply tlirow up little 

 branches above the 



