PLANTS THAT LIVE ON OTHER PLANTS 
tures. They have not developed as have the plants that 
have had to manufacture their own food. The fungus 
plants, therefore, are without the complicated root sys¬ 
tems, stem and branching systems, flowers and leaves that 
are vital to other plants. 
Most of these fungi attack only those plants that are 
dead or dead parts of plants, causing them to go to pieces 
and disappear. Some of them, on the other hand, may 
set upon living plants and destroy them. Those that at¬ 
tack dead plant products are useful to man when the 
objects attacked are not serving his purposes. 
The fungus secretes ferments which so act upon the 
wood as to cause it to dissolve and be drunk up by the 
guest. Finally only a powder is left which goes back to 
the soil. But when this same fungus attacks the logs of 
which the barn is built or railroad ties and converts them 
into powder, the matter assumes a different aspect. 
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