72 LABORATORY PRACTICE CHAP. XIII 



X. Write out a set of comparisons, stating resemblances 

 and differences between the following sets : 



1. The typical green plants and the green parasites. 



2. The green parasites and the pale parasites. 



3. The pale parasites and the saprophytes. 



XI. Show how a typical plant might be led to become a 

 saprophyte and what changes would take place. Write out 

 your opinions on these points in the form of an essay, stat- 

 ing facts supporting them. 



