DISEASES OF PLANTS 229 



spores are of light color, they will show best on a piece 

 of dark paper. 



Notice how easy it is to blow the spores away. You 

 can see how easily the spores of mold are carried every- 

 where by the wind. Spores float a long time in the air, 

 and it is very hard to get rid of them. 



jams and jellies from mold by pouring a layer of melted 

 paraffin over the top. And we must clean out the 

 bread box with soap and water very often to get rid 

 of mold spores. A little formalin is still better than 

 soap and water, but it must be rinsed away afterwards, 

 as it is poisonous. 



The fungi are not green and cannot make their food 

 from air and water as green plants do (page 73). They 

 take their food from living plants or animals or from 

 dead animal or vegetable matter. 



Some of them grow only on dead matter (either ani- 

 mal or vegetable), and they may do good by helping 

 to get rid of it. Others attack living plants or animals. 

 These cause disease, and some of them do a great deal 

 of harm. The diseases of animals are largely due to 

 minute fungi calledbacteria, which we will study farther 

 on! EeTusHaow look at some fungi which cause dis- 

 eases of plants. 



MOLDS AND RELATED PLANTS 



Every one has seen the blue or green spots on oranges 

 and lemons which are made by mold (figure 131). 



