PLANT DISEASES 



267 



dead and decaying remains of other plants and animals. 

 In fact, they are responsible for this decay since they 

 are the agents which break up the dead plant or animal 

 body into simpler compounds and in so doing derive 

 a certain amount of nutrient material. Good examples 

 of this sort are the fungi which cause the rot of wood or 

 the mold of bread and cheese. These fungi and bacteria 

 are called saprophytes. In brief, then, there are two life 

 habits : first, of parasites, which live on living things, 

 and second, of saprophytes, which get their food from 

 either dead plants or animals. 



Life Story of a Fungus. Although the most con- 

 spicuous difference between the fungi and flowering 



FIG. 135. A Germinating Spore at Different Successive Stages of Several Hours 



Apart. 



The small resulting mycelium is seen below. A caterpillar fungus (Cordyceps) spore. Highly 

 magnified. (Minnesota Plant Diseases.) 



plants lies in the lack of chlorophyll in the fungi, there 

 are also other very great differences. Flowering plants 

 are much higher types of organism than the fungi, 

 just as man is a much higher type of animal than 

 the horse. This difference is clearly seen when one 

 studies the life story of the fungus. The fungus does 

 not produce seeds. Its reproduction nevertheless may 

 be fairly complex ; in fact, one fungus may reproduce in 

 a number of different ways. 



