Distance matrix tree showing the phylogenetic relationship between Hyphomicrobium sp. strain M3 and 16S rDNA clones from activated sludge libraries with the hyphal budding bacteria. Reference strains used were H. vulgare IFAM MC-750 (Y14302), Hyphomicrobium-like sp. strain US-353 (U06473), Hyphomicrobium hollandicum IFAM KB-677 (Y14303), Hyphomicrobium aestuarii DSM 1564 (Y14304), Hyphomicrobium zavarzinii ATCC 27495 (U59506), H. denitrificans DSM 1869 (Y14308), Hyphomicrobium methylovorum DSM 5458 (Y14307), Hyphomicrobium facilis sp. strain H-526 (Y14309), Hyphomicrobium facilis ATCC 27492 (Y14310), Filomicrobium fusiforme DSM 5304 (Y14313), Pedomicrobium austrailicum (X97694), Pedomicrobium americanum (X97692), Pedomicrobium manganicum (X97691), Rhodobacter sphaeroides (D16424), Rasbo bacterium (AF007948), Sphingomonas sp. strain B28161 (AJ001052), N. winogradskyi ATCC 14123 (L35507), Xanthobacter tagetidis (X99469), and Bradyrhizobium japonicum USDA110 (D13430). Bootstrap values per 1,000 bootstrap analyses are presented for values greater than 650. Clone sequences from the activated-sludge libraries from this study and Hyphomicrobium sp. strain M3 are in boldface.