CHAPTER NINETEEN 



BACTERIA AND FUNGI 



THE seed plants and algae which have been described manu- 

 facture their own food. Both of them are independent of 

 other plants and both are self-supporting. They are called 

 autophytes, since they make their own food and can live 

 without the assistance of other plants. There are many 

 other plants, including a few of the seed plants, which lack 

 chlorophyll and are unable to manufacture their own food. 

 There are two groups of these dependent plants, saprophytes 

 and parasites. 



Saprophytes live on organic substances which have been 

 manufactured by other plants or animals. The mold that 

 develops on bread is a good example of a plant of this kind. 

 The starch, sugar, and protein in the bread were made orig- 

 inally by wheat plants ; and the mold, therefore, derives its 

 nourishment from substances previously manufactured by a 

 green plant. It grows as well in the dark as in the light, be- 

 cause its food is already prepared. It needs merely to digest 

 the food and absorb it into its own body. The mushrooms 

 are mostly saprophytes, living on fallen leaves, tree trunks, 

 and humus. The Indian pipe is an example of a flowering 

 plant that secures its food in the same way. 



Parasites take their food directly from other living plants, 

 or from animals. The mistletoe is a common parasite on 

 various trees in the Southern states. Its seeds are sticky and 

 adhere to the bark of trees. When a seed germinates, the 

 hypocotyl penetrates the bark and grows inward to the 

 cambium and the food-conducting tissue. There it reaches 

 the food made by the tree and appropriates some of it to 

 its own use. The plant on which a parasite lives is called its 



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