the middle lamella but without action on cellulose. Nitrites produced from nitrates. No ammonia in broth. Pigment insoluble in water, alcohol, ether, chloroform or dilute acids. Temperature relations: Optimum, 30° C. Minimum, between 5° and 6° C. Maximum, 45° C. Thermal death point, 60° C. Source: Isolated from the mango in Africa. Habitat: Causes a disease of the mango (Mangifera indica) . 17. Erwinia rhapontici (Millard, 1924) Burkholder, 1948. {Phyiomonas rhapontica (sic) Millard, Univ. Leeds and Yorkshire Council for Agr. Ed. Bui. 134, 1924, 111; Envinia rhapontici Burkholder, in Manual, 6th ed., 1948, 475; Pectobacterium rhapontici Patel and Kulkarni, Indian Phj'topath., 4, 1951, 80.) rha.pon'ti.ci. Gr. neut.n. rhaponticum specific epithet of Rheum rhaponticum, rhu- barb; M.L. gen. noun, rhapontici of rhubarb. Description taken from Metcalfe (Ann. of Appl. Biol., 27, 1940, 502), where he suggests that this species belongs in Erwinia. Rods, 0.5 to 0.8 by 1.2 to 1.5 microns. Mo- tile by means of 3 to 7 peritrichous flagella. Gram-negative. Gelatin stab: Beaded growth. No lique- faction. Infusion agar: Colonies circular, convex, smooth, glistening, translucent, with mar- gins entire, 2 to 3 mm in diameter in 48 hours at 25° C. Rhubarb agar: Colonies slightly larger, often with a yellowish tinge. Tryptophane broth: Turbid with fragile pellicle, a slight rim and slight flocculent deposit. Alilk: Acid in 3 to 4 days with or without slight curd separation. No clotting. Indole not produced. Hydrogen sulfide not produced. Cohn's solution: Moderate growth. Acid but no gas from arabinose, xjdose, glucose, galactose, fructose, mannose, lac- tose, maltose, sucrose, mannitol, glycerol and salicin. Acetylmethylcarbinol produced . Growth in citrate solution. Starch not hydrolj^zed. Nitrites produced from nitrates. Chromogenesis: Water-soluble, pinkish pigment in various media. Growth from 0° to 37° C. and possibly higher. Distinctive characters: Differs from Er- winia aroideae in that it does not liquefy gelatin nor clot milk and is chromogenic. It also has a limited host range. Source: Isolated from rotting rhubarb crowns. Metcalfe used 6 strains from various sources in describing this pathogen. Habitat: Causes a crown-rot of rhubarb (Rheum rhaponticum) . TRIBE III. SERRATIEAE BERGEY, BREED AND MURRAY, 1938. (Preprint, Manual, 5th ed., 1938 (October), vi.) Ser.ra.ti'e.ae. M.L. gen. noun Serralia type genus of the tribe; -eae ending to denote a tribe; M.L. fem.pl.n. Serratieae the Serratia tribe. Characters as for the genus. There is a single genus. Genus VII. Serratia Bizio, 1823, emend. Breed and Breed, 1927* (Bizio, Polenta porporina, Biblioteca italiana o sia Giornale de lettera, scienze e arti, 30, 1823, 288; Zoagalactina Sette, Memoria storico-naturale sull'arrossimento straordinario di alcune sostanze alimentose osservato nella provincia di Padova I'anno 1819. Venezia,
- Revised by Prof. Robert S. Breed, New York State Experiment Station, Geneva, New
York, November, 1937; further revision by Prof. Robert S. Breed, July, 1955.
