516 



TEXTBOOK OF BOTANY 



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Staphylococcus aureus Diplococcus pneumoniae Staphylococcus pyogenes 



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Bacillus subtilis 



Corynebacterium diphtheriae 



Eberthella typhi 



Vibrio comma Spirillum volutans Treponema pallidum 



Fig. 229. Various types of bacteria. Copyright by General Biological Supply House. 



Except for the sources of the reduced nitrogen and sulfur, such organ- 

 isms are independent of other Hving plants. At the other extreme is the 

 obligate parasite that grows only in the living tissues of another organ- 

 ism. Between these two extremes are the various saprophytes that live 

 upon dead tissues and products of other organisms. 



The autophytes among bacteria include the nitrifying bacteria which 

 oxidize ammonia to nitrites and nitrates; the iron bacteria which oxidize 

 ferrous to ferric salts; and some sulfur bacteria which oxidize reduced 

 sulfur. These are extremely important in soil development and will be 



