LABORATORY PRACTICE 



CHAPTER XIII 



EPIPHYTES, PARASITES, AND SAPROPHYTES 



WE have, thus far, been studying plants with roots spread 

 out under ground and obtaining food for the plant from the 

 earth. These plants have also been in the possession of 

 green leaves, well developed, acting as foliage, to obtain 

 materials from the air for the use of the plant and working 

 over the materials thus obtained by themselves and by the 

 roots, and manufacturing from them the substances needed 

 by the plant for its own processes of life. 



Since we are about to study several plants which live in 

 different ways from the ordinary plants, we shall find it to 

 our advantage to remember that the ordinary or typical plant 

 behaves as follows : 



1. It buries its roots under the surface of the earth in order 



that it may obtain water and whatever is dissolved 

 in it. 



2. It spreads out its leaves into the air to expose them to 



the air and the sunlight. 



3. Its leaves are green as long as they are healthy, but turn 



yellow as they begin to die or are deprived of sun- 

 light. 



I. Take one of the Orchids of the greenhouses which are 

 grown on hanging pieces of wood. Notice : 



