THE ROOT 17 



phyllum, of him-sagar or Kalanchoe, and of Begonia 

 are often seen to develop such adventitious roots. 



Roots usually grow underground, and serve to fix 

 the plant to the ground, so that the plant may not be 



Fig. 15. — The Screw-pine or Itia, with stilted Root-s g^rowing from the Stem 



at the mercy of the winds and the waves. But there 

 are roots which are aerial, that is, which grow and 

 live in the air without any contact with the soil. 

 Most of the Orchids (fig. 16) germinate on branches of 

 trees, and remain clinging to them by the aerial roots, 



( c 945 ) 3 



