[living organisms]
 see Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
  
 Superkingdom Eukaryota Whittaker & Margulis, 1978
 see Domain Eukaryota Chatton, 1925
    
 Kingdom Plantae Haeckel (1866) - plants
      
 Subkingdom Biliphyta Caval.-Sm. (1981) - red algae and glaucophytes
 see Kingdom Plantae Haeckel (1866)
        
 Phylum Rhodophyta Wettst. (1901) - red algae
          
 Subphylum Eurhodophytina G.W.Saunders & Hommers. (2004)
            
 Class Florideophyceae Cronquist (1960)
              
 Subclass Hildenbrandiophyceae M.A. Ruggiero, D.P. Gordon, Orrell, N. Bailly, Bourgoin, Brusca, Caval.-Sm., Guiry & P.M.Kirk (2015), orth. inval. [monotypic]
 see Subclass Hildenbrandiophycidae G.W.Saunders & Hommers. (2004)
                
 Order Hildenbrandiales Pueschel & K.M.Cole (1982)