Gelatin: No liquefaction. Milk: Growth, but no visible change in the milk. No growth with ammonium salts, nitrates or asparagine as a source of nitrogen. No growth in peptone water without carbohydrates. Invertase secreted. Starch not hj'drolyzed. Temperature relations: Optimum, about 25° C. Maximum, 37° C. Distinctive characters: Differs from Xanthomonas vasculorum, which produces a large gummy type of colony and which is a very active organism biochemically. The two pathogens also differ in the type of lesion they produce on sugar cane. Source : Isolated by D. S. North (Colonial Sugar Ref. Co., Sydney, N. S. Wales, Agr. Rept., 8, 1926, 1) from white stripe and leaf scald of sugar cane in Australia. Habitat: Vascular pathogen of sugar cane, Saccharum officinarum.
Group II.—Saprophytic species.
4. Pseudomonas trifolii Huss, 1907. (Huss, Cent. f. Bakt., II Abt., 19, 1907, 68; Xanthomonas trifolii James, Canadian Jour. Microbiol., 1, 1955, 479.) tri.fo'li.i. L. trifoUum trefoil, clover; M.L. neut.n. TrifoUum generic name of clover; M.L. gen. noun trifolii of TrifoUum. Rods, 0.5 to 0.7 by 0.75 to 2.0 microns, occurring singly, in pairs and in chains. Motile, possessing a single polar flagellum. Gram-negative. Gelatin colonies: Convex, smooth, moist, glistening, grayish yellow. Gelatin stab: Napiform liquefaction. Agar colonies: Small, circular, grayish, becoming brownish yellow. Agar slant: Yellowish, becoming brown- ish yellow streak, lacerate margin. Broth: Turbid, with grayish yellow pel- licle and sediment. Litmus milk: Slowly coagulated; alkaline; with yellow ring. Potato: Thick, yellowish, fiat, smooth, glistening. Hydrogen sulfide produced. Indole produced. Acid from glucose, sucrose, xylose, arabi- nose and mannitol. No acid from lactose. Nitrites produced from nitrates. Cultures have an agreeable odor. Volutin formed. Aerobic, facultative. Optimum temperature, between 33° and 35° C. Source: Isolated from clover hay. Habitat: Evidently a common organism on the leaves of plants.
5. Pseudomonas xanthe Zettnow, 1916. Cent. f. Bakt., I Abt., Orig., 77, 1916, 220.) xan'tha. Gr. adj. xanthus yellow. Rods 0.5 to 0.6 by 0.4 to 1.4 microns. Motile, possessing a single or occasionally two or more very long (20 microns) polar flagella. Gram-negative. Gelatin colonies: Circular, yellow, granu- lar. Gelatin stab: Pale yellow surface growth. Brownish j^ellow under surface colonies. Saccate liquefaction. Agar slant: Dark yellow, glistening, with dark yellow sediment in water of condensa- tion. Pigment not water-soluble. Broth: Turbid. Milk becomes rose-yellow in 4 weeks with- out anj^ other change. Potato: Grayish yellow to brownish growth. Indole produced. Nitrites produced from nitrates. Acid produced from glucose, sucrose and maltose. Starch hydrolyzed. Blood serum not liquefied. Aerobic, facultative. Optimum temperature, 30° C. Source: Air contamination.
6. Pseudomonas caudata (Wright, 1895) Conn, 1919. (Bacillus caudatus Wright, Memoirs Nat. Acad. Sci., 7, 1895, 444; Conn, Jour. Agr. Res., 16, 1919, 313.) cau.da'ta. L. noun canda a tail; M.L. adj. caudatus having a tail. Rods long, granular, slender, occurring singly, in pairs and in chains. Appear like cocci in old cultures. Motile, possessing a polar flagellum (Conn). Gram-negative. Gelatin colonies: Yellow, translucent, smooth, undulate. Gelatin stab: Villous growth in stab. Crateriform liquefaction.
