plantenrijk Haeckel (1866) - plants
   [Division] Protophyta Sachs 1874 - primitive plants
     Class Schizomycetes Nägeli 1857 (Approved Lists 1980) - bacteria and related forms
       Order Pseudomonadales Orla-Jensen 1921 (Approved Lists 1980)
         1 Family Chlorobacteriaceae
         2 Family Methanomonadeceae
         3 Family Nitrobacteriaceae see Family Bradyrhizobiaceae Garrity et al. 2001 nom. ined.
         4 Family Pseudomonadaceae Winslow et al. 1917 (Approved Lists 1980)
         5 Family Siderocapsaceae
         6 Family Spirillaceae Migula 1894 (Approved Lists 1980)
         7 Family Thiobacteriaceae see Family Thiotrichaceae