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. Xanthomonas 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.
