10 



THE BOOT 



hairs soon die : they do not grow into roots. New ones 

 form as the root grows. 



31. AERIAL ROOTS. Although most roots bury them- 

 selves in the soil, there are some which grow above ground. 

 These usually occur on climbing plants, the roots becoming 



13. Aerial roots of an orchid. 



14. Indian corn, showing the 

 aerial roots at oo. 



supports or fulfilling the office of tendrils. These aerial 

 roots usually turn away from the light, and therefore enter 

 the crevices and dark places of the wall or tree over which 

 the plant climbs. The trumpet creeper (Fig. 12), true or 

 English ivy, and poison ivy, climb by means of roots. 



32. In some plants, all the roots are aerial; that is, the 

 plant grows above ground, and the roots gather food from 

 the air. Such plants usually grow on trees. They are 



