Use of secondary data in numerical taxonomy of the genus Erwinia.

Lockhart, W. R. (Iowa State University, Ames), and Karen Koenig. Use of secondary data in numerical taxonomy of the genus Erwinia. J. Bacteriol. 90:1638-1644. 1965.-Numerical methods were used to study 34 bacterial cultures, including several species of Erwinia and selected representatives of other genera of the Enterobacteriaceae. Separate computations were made by use of varying amounts of secondary data (i.e., information regarding descriptive or quantitative characters applicable only to organisms yielding a positive result in another primary character). Substantially the same groupings of the test organisms were obtained in all computations, but definition of groups seemed to be more precise when secondary data were included. The results confirm proposals by other workers that E. carotovora, E. aroideae, E. atroseptica, and E. ananas be placed in a single species, separate from E. amylovora. Limited evidence suggests that E. nimipressuralis and E. chrysanthemi may be distinct species, and that some strains of E. amylovora are not very similar either to one another or to other members of the Enterobacteriaceae.