show Abstracthide AbstractA pneuma yeast-like fungus that causes pulmonary infections in mice. The growth in lungs appears obligate, as the fungus can not currently be grown in culture. Other species of <i>Pneumocystis</i> infect different hosts, such as <i>P. jirovecii</i>, which infects humans. <i>Pneumocystis</i> species are found in the Taphrinomycotina subdivision of Ascomycota, along with <i>Schizosaccharomyces pombe</i>.