[organisms] see Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
   Domain Bacteria Woese et al. 1990
     Phylum Firmicutes corrig. Gibbons and Murray 1978 (Approved Lists 1980)
       1 Class "Clostridia" Garrity et al. 2001 nom. ined. see Class Clostridia Rainey 2010
       2 Class Mollicutes Edward and Freundt 1967 (Approved Lists 1980)
       3 Class "Bacilli" Garrity et al. 2001 nom. ined. see Class Bacilli Ludwig et al. 2010