prokaryotes - bacteria see Domain Bacteria Woese et al. 1990
   Domain "Bacteria" Woese et al. 1990
     Phylum "Proteobacteria" Garrity et al. 2005 see Superphylum Proteobacteria Craig et al. 2010
       Class Alphaproteobacteria Garrity et al. 2006
         Order Rhizobiales Kuykendall 2006
           01 Family "Aurantimonadaceae" Garrity et al., 2003
           02 Family Bartonellaceae Gieszczykiewicz 1939 (Approved Lists 1980)
           03 Family Beijerinckiaceae Garrity et al. 2006
           04 Family Bradyrhizobiaceae Garrity et al. 2006
           05 Family Brucellaceae Breed et al. 1957 (Approved Lists 1980)
           06 Family Cohaesibacteraceae Hwang and Cho 2008 [monotypic]
           07 Family Hyphomicrobiaceae Babudieri 1950 (Approved Lists 1980)
           08 Family Methylobacteriaceae Garrity et al. 2006
           09 Family Methylocystaceae Bowman 2006
           10 Family Phyllobacteriaceae Mergaert and Swings 2006
           11 Family Rhizobiaceae Conn 1938 (Approved Lists 1980)
           12 Family Rhodobiaceae Garrity et al. 2006
           13 Family Roseiarcaceae Kulichevskaya et al. 2014 [monotypic]
           14 Family Xanthobacteraceae Lee et al. 2005
           15 Genus Alsobacter Bao et al. 2014, incertae sedis
           16 Genus Amorphus Zeevi Ben Yosef et al. 2008, incertae sedis
           17 Genus Bauldia Yee et al. 2010, incertae sedis
           18 Genus Methyloceanibacter Takeuchi et al. 2014, incertae sedis
           19 Genus Vasilyevaea Yee et al. 2010, incertae sedis