BACTERIA 115 



GENERA OF THE EUBACTERIALES 



I. NITROBACTERIACE.E 



Fixing nitrogen or oxidizing its compounds 

 Fixing free nitrogen 



Cells large; in soil 7. Azotobacter 



Rods minute; in roots of leguminous 



plants 8. Rhizobium 



Oxidizing nitrogen compounds 



Oxidizing ammonia 5. Nitrosomonas 



Oxidizing nitrites 6. Nitrobacter 



Not as above 



Oxidizing hydrogen i. Hydrogenomonas 



Oxidizing carbon compounds 



Oxidizing alcohol; branching forms 



common 4. Mycoderma 



Not as above, using simpler carbon 

 compounds 



Oxidizing CO 3. Carboxydomonas 



Oxidizing CH 4 2. Methanomonas 



II. MYCOBACTERIACE^; 



Slender rods staining with difficulty and 



acid fast 3. Mycobacterium 



Not as above 



Mycelium and conidia formed 



With aerial hyphae and conidia; usually 



saprophytic soil organisms 2. Nocardia 



Hyphae and conidia not aerial; usually 



parasitic in animals i. Actinomyces 



Not as above; cells rod-like, usually somewhat 

 curved, clubbed, fusiform, or even 

 branched, but never mycelial 

 Thick, long threads, fragmenting into 



short thick rods 6. Leptotrichia 



Not as above 



Cells usually elongate and fusiform, 

 filaments, if formed not branch- 

 ing; stains somewhat irregularly. .5. Fusiformis 

 Cells slightly curved, clubbed, or in 

 old cultures even branching; not 

 filamentous; showing definite bar- 

 red staining 4. Corynebacterium 



III. PSEUDOMONADACE^E 



Generic characters mainly those of family. . i. Pseudomonas 



