24 



ROOTS 



The Banyan tree of the tropical East Indies produces roots 

 from its branches which tend to reach the soil and finally assume 

 the character of tree trunks. Some plants, known, as epiphytes, 

 especially abundant in warm, moist climates, often produce 

 aerial roots which never reach the soil but spread out into 

 the moist air and serve for the absorption of water. The 

 orchids of tropical countries, and the so-called Florida moss of 

 our own Southern States are striking examples of epiphytic 



FIG. 14. Cross-section of stem showing dodder attached by haustoria or parasitic root. 



plants. The orchids in the colder climates are rooted in the 

 soil. 



The aerial roots may also serve for climbing on trees, fences 

 or buildings, stone walls and other firm objects. Climbing 

 plants are frequently injurious to trees, not only because their 

 roots penetrate the minute crevices, but also because they retain 

 the moisture and make favorable conditions for organisms which 

 cause decay. They are also injurious to wooden structures on 

 which they are allowed to grow, in that they retain moisture 

 and cause decay. 



Parasitic Roots. Some plants feed upon other plants by 

 means of roots which penetrate them. They are called parasites, 

 and their roots parasitic roots or Jiaustoria. The mistletoe of 

 the South and the common dodder (Fig. 14) which is much 



