MICROSCOPE AND AGRICULTURE 



stems and flowers may sometimes be seen in clover 

 fields, then clover is its victim. 



More common and more destructive is the little 

 Dodder, a member of the Convolvulus family. Its 

 seeds are very minute and when they germinate 

 they give rise to a seedling not unlike a piece of 

 wire. With one end fixed in the ground, the other 

 waves about till it finds a clover plant round which 

 it twines and not only so but it sends out suckers 

 which microscopic examination shows, penetrate 

 the stem of the clover to rob its food. By pulling 

 a Dodder stem away from the clover we can clearly 

 see a number of holes where the suckers have 

 entered. 



Fungus diseases and insects wage constant war- 

 fare on the farmer's belongings. That we may 

 better understand the structure of the disease- 

 causing fungi we are about to examine, let us 

 refresh our memories concerning that very common 

 fungus, known as white mould and mentioned in 

 an earlier chapter. The reason fungi cause damage 

 to other plants, the one invariable reason, is that 

 they, being unable to manufacture food for them- 

 selves, steal it from the plants on which they grow. 

 Some of them are parasites and steal their food from 

 living animals or plants; others live upon dead 

 animal or vegetable matter and the white mould 

 is one of the latter fungi. 



In most of the fungi which concern us we shall 

 find that there is a mass of minute, thread-like 

 structures forming the main body of the fungus and 



181 



