90 GENERAL SYSTEMATIC BACTERIOLOGY 



2f. Not as above. 



g. Gram-positive; non-motile 



VII. Lactobacillaceae 

 2g. Gram-negative; often motile. 



VI. Bacteriaceae 



3. Artificial Key to the Genera of the Eubacteriales 



a. Nitrobacteriaceae. 



b. Fixing nitrogen or oxidizing its compounds. 

 c. Fixing nitrogen. 



d. Cells large; in soil 7. Azotobacter 



2d. Rods minute; in roots of leguminous plants. 



8. Rhizobium 

 2c. Oxidizing nitrogen compounds. 



d. Oxidizing ammonia 5. Nitrosomonas 



2d. Oxidizing nitrites 6. Nitrobacter 



2b. Not as above. 



c. Oxidizing hydrogen 1. Hydrogenomonas 



2c. Oxidizing carbon compounds. 



d. Oxidizing alcohol; branching forms common. 



4. Mycoderma 

 2d. Not as above, using simpler carbon compounds. 



e. Oxidizing CO 3. Carboxydomonas 



2e. Oxidizing CH4 2. Methanomonas 



2a. Mycobacteriaceae . 



h. Slender rods, staining with difficulty and acid-fast. 



3. Mycobacterium 

 2b. Not as above. 



c. Mycelium and conidia formed. 



d. With aerial hyphae and conidia; usually saphrophytic soil 



organisms 2. Nocardia 



2d. Hyphae and conidia not aerial; usually parasitic in animals. 



1. Actinomyces 

 2c. Not as above; cells rod-like, usually somewhat curved, clubbed, 

 fusiform, or even branched, but never mycelial, 

 d. Thick, long threads, fragmenting into short, thick rods. 



6. Leptotrichia 

 2d. Not as above. 



e. Cells usually elongate and fusiform; filaments, if 

 formed, not branching; staining somewhat irregularly. 



5. Fusiformis 



2e. Cells slightly curved, clubbed, or in old cultures even 

 branching ; not filamentous ; showing definitely barred 



staining 4. Corynebacterium 



3a. Pseudomonadaceae. 



Generic characters mainly those of family. . . 1. Pseudomonas 

 4a. Spirillaceae. 



b. Flagellum single (rarely 2 or 3) 1. Vibrio 



