Natura - nature
   actualia - actual entities
     Mundus Plinius - physical world
       naturalia - natural bodies
         Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
           Domain Bacteria Woese et al. 2024
             Kingdom Pseudomonadati (Gibbons and Murray 1978) Oren and Göker 2024
               Phylum Planctomycetota Garrity and Holt 2021
                 Class Phycisphaerae Fukunaga et al. 2010
                   Order Phycisphaeralesᵀ Fukunaga et al. 2010 [monotypic]
                     Family Phycisphaeraceaeᵀ Fukunaga et al. 2010
                       1 Genus Algisphaera Yoon et al. 2014 [monotypic]
                       2 Genus Mucisphaera Kallscheuer et al. 2022
                       3 Genus Natronomicrosphaera Sorokin et al. 2025
                       4 Genus Phycisphaeraᵀ Fukunaga et al. 2010 [monotypic]
                       5 Genus Poriferisphaera Kallscheuer et al. 2021