152 ORDER I. PSEUDOMONADALES 



terium wieringae Elliott, Man. Bact. Plant Rods 0.5 by 2.0 microns. Motile with 1 to 



Pathogens, 1930, 264; Saviilescu, Anal. 5 polar flagella. Gram-negative. 



Acad. Romane, III, 22, 1947, 11.) Beef -agar colonies: Smooth, round, white 



wie'ring.ae. Named for Dr. K. T. Wie- to grayish, fluorescent, 



ringa, the bacteriologist who first described Milk: Cleared in 5 days. Not coagulated, 



the species; M.L. gen. noun wieringae of Nitrites not produced from nitrates. 



Wieringa. No gas from sugars. 



Because Bacterium betae Chester (Ann. Temperature relations : Optimum between 



Rept. Del. Col. Agr. Exp. Sta., 9, 1897, 53) 28° and 30° C. Minimum, 4° C. Maximum, 



may be a pseudomonad, the more distinctive 37° C. 



species name proposed by Elliott has been Source: Isolated from vascular rot of 



retained. beets in Holland. 



Description from Elliott (op. cit., 1930, Habitat: Pathogenic on beets, Beta vul- 



264). garis. 



Genus II. Xanthomonas Dowson, 1939 * 



{Phijtomonas Bergey et al., Manual, 1st ed., 1923, 174; not Phytomonas Donovan, Lancet, 



177, 1909, 1495 (type species (monotypy) Phytomonas davidi Donovan, a flagellate); 



Dowson, Zent. f. Bakt., II Abt., 100, 1939, 187.) 



Xan.tho'mo.nas or Xan.tho.mo'nasf. Gr. adj. xanthus yellow; Gr. fem.n. monas unit, 

 monad; M.L. fem.n. Xanthomonas yellow monad. 



Cells usually monotrichous. A yellow, non-water-soluble pigment is produced on agar. A 

 diffusible, brown color infrequently occurs in beef extract agar. Proteins are usually readily 

 digested. Milk usually becomes alkaline. Hydrogen sulfide is produced. Asparagine is not 

 sufficient as an only source of carbon and nitrogen. Acid (and also gas in one species, No. 

 19) produced from mono- and disaccharides. Some species liquefy a pectin medium, others 

 do not (Burkholder and Starr, Phytopath., 38, 1948, 500). Mostly plant pathogens causing 

 necroses. 



The type species is Xanthomonas hyacinthi (Wakker) Dowson. 



Key to the species of genus Xanthomonas. 



I. Colonies yellow; pigment non -water-soluble. 

 A. Gelatin liquefied. 



1. Starch hydrolysis feeble. 



a. Nitrites not produced from nitrates. 



1. Xanthomonas hyacinthi. 



2. Xanthomonas pruni. 



3. Xanthomonas vitians. 

 aa. Nitrites produced from nitrates. 



4. Xanthomonas beticola. 



5. Xanthomonas rubrilineans . 



2. Starch hydrolysis strong. 



a. Nitrites not produced from nitrates. 



b. No brown pigment in beef -extract agar. 



6. Xanthomonas barbareae. 



7. Xanthomonas begoniae. 



8. Xanthomonas betlicola. 



9. Xanthomonas campestris. 



* Prepared by Prof. Walter H. Burkholder, Cornell University, Ithaca, N. Y., June, 

 1943; revised November, 1953. 

 t The former accords with the Latin rules of accentuation; the latter is in common usage. 



