CHAPTER VII 
DEPENDENT PLANTS 
THE plants that we have seen in the lessons already stud- 
ied have possessed the green coloring-matter, chlorophyll; 
which means that they have the ability to construct their 
own nourishment from quite simple substances. There are 
many plants, however, which are devoid of chlorophyll, and 
which obtain their nourishment either directly or indirectly 
from plants that are able to manufacture their own food. 
These are classed as dependent plants, and the forms of de- 
pendency that they assume are quite varied. Some of these 
plants, known as parasites, attack living plants and animals, 
and take their food material from them; some, known as 
saprophytes, live upon dead and decaying organisms; and 
some live with other organisms, taking some foods from 
them, but giving in return advantages of some kind to com- 
pensate for food taken. The last are known as mutualists. 
LESSON XXI 
Plant parasites 
Materials.—Lilac-mildew, grape-mildew, wheat-rust, 
water-mold (Saprolegnia), tree-destroying toadstools, corn- 
smut, dodder, mistletoe, and any other available plants that 
live upon other living things. If nearly all the materials 
suggested can be had it will be advisable to have two or 
more lessons upon this subject. 
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