Ascomycota Caval.-Sm. (1998) - sac fungi
   Order Pneumocystidales O.E. Erikss. (1994)
     Family Pneumocystidaceae O.E. Erikss. (1994)
       Genus Pneumocystis P. Delanoë & Delanoë (1912)
         Pneumocystis carinii J.K. Frenkel (1999)