Chapter IV. 



Fungi. Plant Partnerships. Parasitism. 



Equal partnerships of plants. Plants often live in very inti- 

 mate relationship with each other. Sometimes this intimacy 

 works out to the injury of one and to the benefit of the other. 

 It may result in benefit to both partners or in what may be 

 called an equal partnership of plants. When two plants find 

 such an intimacy beneficial they may learn to modify their 



FIG. 21. A lichen. A plant with equal partnership of fungus and alga. After Atkinson. 



habits and even their structure in such a way that both may re- 

 linquish the fulfillment of some duties and will depend on the 

 partner for the accomplishment of that work. In this way the 



