THE ROOT THE FORMS OF ROOTS 



35 



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

 plant $ climbs. The trumpet creeper (Fig. 36), true or 

 i English ivy, and poison ivy climb by 

 means of roots. 



I 



FIG. 37. AERIAL ROOTS OF AN ORCHID. 



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 known as 



'1 



epiphytes or air-plants. The most fa- 

 FIG. 36. AERIAL ROOTS . . * 



OF TRUMPET CREEPER miliar examples are some of the tropi- 



OR IECOMA. ca ] orc hids, which are grown in glass- 



houses (Fig. 37). Rootlike organs of dodder and other 

 parasites are discussed in a future chapter. 



