, AND JOHN G. HOLT. Numerical taxonomy of certain coryneform bacteria. J. Bacteriol. 20:921-927. 1965-An electronic computer was used to sort 32 strains of coryneforms into groups with the tree-sort program. The similarity values obtained in this procedure were then used to construct a dendrogram depicting the. phenetic resemblance among the taxa. The results indicated that all the phytopathogens studied were sufficiently distinct from the type species, Corynebacterium diphtheriae, to be excluded from the genus Corynebacterium. The grouping of some of the phytopathogens with Microbacterium lacticum is discussed. C. fascians appeared so distinct from the other strains studied that it should probably be excluded from the Corynebacteriaceae. The phenetic resemblance of Brevibacterium linens and Arthrobacter globiformis was emphasized, and the new combination, Arthrobacter linens, was proposed. In addition, because of distinct dissimilarity from the type species, it would seem desirable to exclude Arthrobacter tumescens from the genus Arthrobacter. The justification for classifying Kurthia zopfii in a family separate from the Corynebacteriaceae would appear to be open to serious question. It was concluded that the present taxonomic positions of Listeria monocytogenes, Cellulomonas biazotea, and Cellulomonas fimi are satisfactory.