GENERAL SYSTEMATIC BACTERIOLOGY 81 



II. Epiphytes, usually on leaves and stems of water plants. Iron oxid deposited 

 upon the capsule Tribe III. Siderocapseae 



Key to the genera of the Streptococceae 



A. Cells occurring normally in chains. 



I. Usually parasitic. Not forming zoogloeal masses in sugar solutions 



Genus 1. Streptococcus 

 II. Saprophytic, occurring in cane sugar solutions in zoogloeal masses. 



Genus 2. Leuconostoc 



B. Cells not occurring usually or characteristically in chains. 



I. Parasitic. Cells in pairs, growth as a rule meagre. No pigment 



formed. 



a. Gram-positive Genus 3. Diplococcus 



b. Gram-negative Genus 4. Neisseria 



II. Cells in irregular groups, usuallj^ parasites, growth as a rule good, 

 pigment usually orange or white. 



Genus 5. Staphylococcus 



Key to the genera of Micrococceae 



A. Cells not in regular packets. 



1. Pigment generally yellow Genus 1. Micrococcus 



2. Pigment red Genus 2. Rhodococcus 



B. Cells in regular packets. Pigment yellow or orange. 



Genus 3. Sarcina 



Key to the genera of Siderocapseae 

 One genus only, Siderocapsa. 



Key to the tribes of the Bacteriaceae 



A. Cells not acid-fast. 



I. Typically producing endospores under favorable conditions. 



Tribe I. Bacilleae 

 II. Not producing endospores.. Tribe II. Bacterieae 



B. Cells acid-fast, frequently showing some tendency to branching. 



Tribe III. Mycobacterieae 



Key to the genera of Bacilleae 



A. Usually a single endospore formed within each cell. 



I. Aerobic usually Gram-positive, as a rule liquefying gelatin, spores 

 usually not distorting rods when formed. 



Genus 1. Bacillus 



II. Anaerobic or microaerophilic usually. 



a. Spores produced at extreme tip of cells, forming typical drum- 



sticks Genus 2. Plectridium 



b. Spores not produced at extreme tip of cells, at least not forming 



drumsticks. Cells usually somewhat swollen when spores are 

 formed Genus 3. Clostridium 



