Natura - nature
   actualia - actual entities
     Mundus Plinius - physical world
       naturalia - natural bodies
         "crystal-kingdom"
           chemical substances
             chemical compounds
               Class esters [acyl-XR, etc.; R'kE(=O)l(OH)m (l≠0; ≥1 (OH):=(XR)), etc.; X=O,S,Se,Te,etc.; R≠H]
                 Class phosphoglycerides [RC(=O)OCH2CH(OC(=O)R)CH2OP(=O)(OR)2]
                   Class cephalins [RC(=O)OCH2CH(OC(=O)R)CH2OP(=O)(O-)OCH2CH2N+H3]
                   Class lecithins [RC(=O)OCH2CH(OC(=O)R)CH2OP(=O)(OH)OCH2CH2N+(CH3)3]
                   Class phosphatidic acids [RC(=O)OCH2CH(OC(=O)R)CH2OP(=O)(OH)2]