Histoplasma is a genus of dimorphic fungi commonly found in guano (the feces of birds and bats) and in soil where guano falls. In modern taxonomy, the genus contains a single species, Histoplasma capsulatum, that has several infraspecific varieties. The normal variety is the causative agent of classic histoplasmosis; Histoplasma capsulatum var. duboisii causes African histoplasmosis; and Histoplasma capsulatum var. farciminosum causes epizootic lymphangitis in horses. The duboisii and farciminosum varieties have each formerly been classified as separate species, Histoplasma duboisii and Histoplasma farciminosum.