FAMILY IV. PSEUDOMONADACEAE 



179 



ste.war'ti.i. Stewart patronymic; JVI.L. 

 gen. noun stewartii of Stewart. 



Description from Smith (U. S. Dept. 

 Agr., Div. Veg. Phys. and Path., Bull. 28, 

 1901). 



Rods 0.4 to 0.7 by 0.9 to 2.0 microns. 

 Encapsulated. Non- motile (McCulloch, 

 Phytopath., 8, 1918, 440). Gram-negative. 



Gelatin: No liquefaction. 



Nutrient agar colonies: Small, round, 

 yellow. 



Broth: Growth feeble with whitish ring 

 and yellow precipitate. 



Milk: Yellow ring but no visible action 

 on the milk. Slightly acid. 



Nitrites not produced from nitrates. 

 McNew (Phytopath., 28, 1938, 773) states 

 that less virulent strains assimilate only 

 organic nitrogen; those of intermediate 

 virulence assimilate nitrogen from inorganic 

 salts without reduction of nitrates to ni- 

 trites; virulent strains reduce nitrates to 

 nitrites. 



Hydrogen sulfide not produced. 



Indole production slight or none. 



Reduction of methylene blue in Dun- 

 ham's solution feeble or doubtful. 



Acid but no gas from glucose, galactose, 

 sucrose, mannitol and glycerol. No acid 

 from maltose. Acid from fructose, arabinose 

 and xylose (McNew, loc. cit.); also from 

 lactose and mannose (Dowson, op. cit., 

 100, 1939, 190). 



Starch not hydrolyzed. 



Temperature relations: Optimum, 30° C. 

 Maximum, 39° C. Minimum, 8° C. 



Chemical tolerance: Optimum pH be- 

 tween 6.0 and 8.0. Limits, about pH 4.5 to 

 8.5. 



8 per cent salt restricts growth. 



Strict aerobe. 



Source: From wilted sweet corn. 



Habitat: Pathogenic on corn, Zea mays. 

 Sweet corn very susceptible and field corn 

 slightly so. 



2. Xanthomouas tardicrescens (Mc- 

 Culloch, 1937) Dowson, 1943. (Bacterium 

 tardicrescens McCulloch, Phytopath., £7, 

 1937, 135; Dowson, Trans. Brit. Mycol. Soc, 

 26, 1943, 12.) 



tar.di.cres'cens. L. adj. tardus slow; L. 



part. adj. crescens growing; M.L. adj. tardi- 

 crescens slow growing. 



Rods 0.6 to 0.8 by 1.58 microns. Motile 

 with a polar flagellum. Gram-negative. 



Gelatin: No liquefaction. 



Beef -extract agar colonies: Circular, 

 mustard -yellow, edges entire, 1.0 to 1.5 mm 

 in diameter. 



Broth: Light clouding. 



Milk: Slightly alkaline. Clearing after 5 

 to 6 weeks. 



Nitrites produced from nitrates. 



Indole not produced. 



Hydrogen sulfide not produced, or feebly 

 so. 



Acid but no gas from glucose, fructose, 

 galactose, arabinose, xylose and rhamnose. 

 Alkaline reaction from salts of citric, malic 

 and succinic acids. 



Starch not hydrolyzed. 



Not lipolytic (Starr and Burkholder, 

 Phytopath., 82, 1942, 603). 



Temperature relations: Optimum, 26° C. 

 Maximum, 32° C. Minimum, 5° C. (McCul- 

 loch, Phytopath., 28, 1938, 648). 



Chemical tolerance: Optimum pH be- 

 tween 6.5 and 7.5. Growth slight at 5.8 and 

 8.0 (McCulloch, loc. cit.). 



No growth with 3 per cent salt (McCul- 

 loch, loc. cit.). 



Aerobic. 



Distinctive character: Very slow grower. 



Source: Isolated by McCulloch and by 

 Burkholder from blighted iris leaves. 



Habitat: Pathogenic on Iris spp. 



3. Xanthomonas albilineans (Ashby, 

 1929) Dowson, 1943. {Bacterium albilineans 

 Ashby, Trop. Agr., Trinidad, 6, 1929, 135; 

 Dowson, Trans. Brit. Mycol. Soc, .^5,1943, 

 11.) 



al.bi.li'ne.ans. L. adj. albus white; L. 

 part. adj. lineans striping; M.L. adj. albili- 

 neans white-striping. 



Description from Martin, Carpenter and 

 Weller (The Hawaiian Planters' Record, 

 36, 1932, 184). 



Rods, 0.25 to 0.3 by 0.6 to 1.0 micron, 

 occurring singly or in chains. Motile with a 

 polar flagellum. Gram-negative. 



Agar colonies: After 7 to 10 days, minute 

 transparent drops, moist, shining. Honey- 

 yellow to Naples -yellow. 



