FAMILY RHIZOBIACEAE 



231 



Nutrient agar slant: Growth scanty, 

 flat, glistening, smooth, translucent, 

 whitish. 



Broth: Growth slight. Xo sediment. 



Milk: No acid. 



Nitrites produced from nitrates. 



Hydrogen sulfide production slight. 



Acid but not gas from glucose, fruc- 



tose, galactose and maltose. No acid or 

 gas from lactose, sucrose or glycerol. 



Starch not hydrolyzed. 



Facultative aerobe. 



Source : Isolated from galls on Douglas 

 fir in California. 



Habitat : Pathogenic on Douglas fir, 

 Pseudoisuga taxifolia. 



Genus III. ChiOTD.oha.cteTiuia Bergonzini.* 



(Ann. Societa d. Naturalisti in Modena, Ser. 2, 14, 1881, 153.) Greek, chroma, 

 color; M. L., bacterium, a small rod. 



Rods, 0.4 to 0.8 by 1.0 to 5.0 microns. Motile with 1 to 4 or more flagella. Gram- 

 negative. A violet pigment is formed which is soluble in alcohol, but not in water or 

 chloroform. Grow on ordinary culture media, usually forming acid from glucose, 

 sometimes from maltose, not from lactose. Gelatin is liquefied. Indole is not pro- 

 duced. Nitrate usually reduced to nitrite. Optimum temperature 20-25°C. but 

 some grow well at 37°C. Usually saprophytic soil and water bacteria. 



The type species is Chromobacterium violaceum (Schroeter) Bergonzini. 



Key to the species of genus Chromobacterium. 



I. Motile rods. Single flagellum. 



A. Acid from glucose and maltose. No acid from sucrose. Nitrites produced 

 from nitrates. No growth at 37°C. 



1. Chromobacterium violaceum. 

 II. Motile rods. Flagella generally peritrichous. 



A. Acid from glucose. Nitrites generallj' not produced from nitrates. Good 



growth at 37°C. 



2. Chromobacterium ianthinum. 



B. Generally no acid from glucose. Nitrites produced from nitrates. No 



growth at 37°C. 



3. Chromobacterium amethystinum. 



1. Chromobacterium violaceum 



(Schroeter) Bergonzini. {Bacteridium 

 violaceum Schroeter, Beitrage z. Biol. d. 

 Pflanzen, 1, Heft 2, 1872, 126; Micro- 

 coccus violaceus Colin, Beitrage z. Biol, 

 d. Pflanzen, /, Heft 2, 1872, 157; Cromo- 

 bacterium violaceum (sic) Bergonzini, 

 Ann. Societa d. Naturalisti in Modena, 

 Ser. 2, 14, 1881, 153; Bacillus violaceus 

 Schroeter, Kryptogamen-Flora von Schle- 

 sien, 3, 1886, 157; Streptococctis violaceus 

 Trevisan, I generi e le specie delle 



Batteriacee, 1889, 31 ; Pseudomonas 

 violacea Migula, Arb. a. d. Bakt. Inst. 

 Karlsruhe, 1, 1894, 237; Bacterium vio- 

 laceum Lehmann and Neumann, Bakt. 

 Diag., 1 Aufl., 2, 1896, 58; see 2 Aufl., 2, 

 1899, 262.) From Latin, violaceus, 

 violet-colored. 



Note: Bacterium ianthinum Zopf (Die 

 Spaltpilze, 1885, 68) has been regarded as 

 identical with the above organism 

 by Schroeter (Kryptogamen-Flora von 

 Schlesien, 3, 1, 1886, 157), and by Leh- 



* Adapted by Prof. Robert S. Breed, New York State Experiment Station, Geneva, 

 New York from Cruess-Callaghan and Gorman, Scientific Proc. Royal Dublin Society, 

 21, 1935, 213 in Jan. 1938; further revision, July, 1945 by Robert S. Breed with the 

 assistance of Capt. W. C. Tobie, Sn. C, Old Greenwich, Conn. 



