plantenrijk Haeckel (1866) - plants
   [Division] Protophyta Sachs 1874 - primitive plants
     Class Schizomycetes Nägeli 1857 (Approved Lists 1980) - bacteria and related forms
       Order Spirochaetales Buchanan 1917 (Approved Lists 1980)
         Family Treponemataceae Robinson 1948 (Approved Lists 1980)
           Genus Treponema Schaudinn 1905 (Approved Lists 1980)
             Treponema pallidum (Schaudinn and Hoffmann 1905) Schaudinn 1905 (Approved Lists 1980)