370 GENERAL SCIENCE 



is formed by the contents of two cells flowing together 

 to make one strong cell. This new cell can withstand 

 extreme temperatures and also dry weather. The wind 

 may carry it about as dust, and when it falls into a pond 

 it will start to grow and form a new plant if the tempera- 

 ture is right. These spore cells are usually formed by the 

 union of the cells of two threads lying side by side. 



254. Fungi. The fungi form a very large group of 

 plants that do not have green coloring matter or chloro- 

 phyll, and so cannot make starch of water and carbon 

 dioxide. Their color is mostly white, and they live on 

 the juices of other plants which are living or dead. Those 

 fungi which take their food from living plants are called 

 parasites, and are generally harmful. Those which live 

 on decaying matter are called saprophytes, and most of 

 them are useful except when they grow where they are 

 not wanted. The common fungi are mushrooms, molds, 

 and yeast. 



There are about 400 kinds of edible mushrooms which 

 grow wild in the woods and fields. Some are grown under 

 .cultivation. The part of the mushroom which is eaten 

 is only the spore-bearing part. The roots of the mushroom 

 are in the ground or in decaying matter on which they 

 grow. One mushroom top may produce millions of 

 spores (seed-like organs) which are scattered by the wind. 



The molds are useful in decomposing dead matter so 

 that it can be used again by higher plants. Molds are 

 harmful when they decompose useful dead matter such 

 as lumber and foods. One common kind is the black 

 mold which grows on bread. To grow some, take a piece 

 of old bread, moisten it, and roll it on the floor to gather 

 some dust containing the mold spores, and then put it 

 away for two or three days, being sure to keep it moist. 



