PLANTS WITHOUT CHLOROPHYLL 



131 



the so-called " toadstools ' found in parks or lawns. These 

 plants contain no chlorophyll and hence do not make their own 

 food. They are members of the plant group culled fungi. Such 

 plants are almost as much dependent upon the green plants for 

 food as are animals. But the fungi require for the most part 

 dead organic matter for their food. This may be obtained from 

 decayed vegetable or animal material in soil, from the bodies of 

 dead plants and animals, or even from foods prepared for man. 

 Fungi which feed upon dead organic material are known as sap- 

 rophytes. Examples are the mushrooms, the yeasts, molds, and 

 some bacteria, of which more will be learned later. 



Some Parasitic Fungi. - Other fungi (and we will find this 

 applies to some animals as well) prefer living plants or animals 

 for their food. Thus a tiny 

 plant, recently introduced 

 into this country, known 

 as the chestnut canker, is 

 killing our chestnut trees by 

 the thousands in the eastern 

 part of the United States. 

 It produces millions of tiny 

 reproductive cells known as 

 spores; these spores, blown 

 about by the wind, light on 

 the trees, sprout, and send 

 in under the bark a thread- 

 like structure which sucks 

 in the food circulating in 

 the living cells, eventually 

 causing the death of the 

 tree. A plant or animal 

 which lives at the expense of 

 another living plant or ani- 

 mal is called a parasite. The chestnut canker is a dangerous 

 parasite. Later we shall see that animal and plant parasites de- 

 stroy yearly crops and trees valued at hundreds of millions of 

 dollars and cause untold misery and suffering to humanity. 



Chestnut trees in a New York City park ; 

 killed by a parasite, the chestnut canker. 



