Paracoccidioides brasiliensis causes paracoccidioido­mycosis. It is a dimorphic fungus that exists as a mold in soil and as a yeast in tissue. The yeast is thick­walled with multiple buds ("ship's wheel" appearance), in contrast to Blastomyces dermatitides, which has a yeast with a single bud that has a broad base. Histoplasma capsulatum occurs as an oval budding yeast inside macrophages, whereas Coccidioides is a spherule in tissue, with many endospores within the spherule. Sporothrix, a dimorphic fungus from vegetation, is introduced into the skin and forms a local pustule or ulcer with nodules; round or cigar-shaped budding yeasts are seen in tissue specimens.