30 BACTERIA, YEASTS, AND MOLDS 



Among the colorless plants are a great variety of forms 

 which show wide differences in structure, size, and general 

 appearance. But inasmuch as they all agree in lacking 

 green coloring material, they are, at least from the stand- 

 point of their relations in nature, properly placed in one 

 general class. A method of dividing them, convenient for 

 our purposes, is as follows. 



Colorless Plants 



Higher Fungi. This includes the forms of larger size, 

 known generally as mushrooms, toadstools, wood fungi, 

 rusts, smuts, etc. With these plants we are not particu- 

 larly concerned in the household. 



Molds. Fungi of small size, but yet easily visible to the 

 naked eye, composed of threads. 



Yeasts. Microscopic plants which multiply by a process 

 called budding, composed of oval bodies. 



Bacteria. Still smaller plants that multiply by a process 

 cailtA fission, composed of spherical, rod-shaped, or spiral 

 bodies. 



This classification is not scientifically accurate. The 

 higher fungi include a large number of different types 

 classed by botanists into many subdivisions. But since 

 they are not concerned in household problems we may 

 most conveniently group them together and consider them 

 no further. Scientists also classify yeasts and bacteria 

 still further into smaller groups ; but one does not need 

 to learn them to understand the behavior of these micro- 

 organisms in the home. 



The group of molds also is not a proper scientific divi- 

 sion, since under this head are included several different 



