Uncinocarpus reesii is a species of saprotrophic microfungi that grows in soil and on keratinous materials such as hair, feathers and skin.

Uncinocarpus reesii was first recognized under the name Gymnoascus uncinatus by German taxonomist Michael Emil Eduard Eidam in 1893.

[6][7]In culture, colonies of U. reesii grow moderately fast and are yellowish-white to buff in colour,[8][1] are flat and dense in shape, and range from velvety to powdery in texture.

[4] These appendages are found in the asexual stage as extensions of vegetative hyphae, but only develop fertile spore-bearing structures (gymnothecia) in the sexual morph when compatible strains are mated.

When the asexual morph of U. reesii develops these hooked appendages, they are referred to as "pseudogymnothecia", due to their similar appearance but lack of a spore-bearing structure.

The ability of U. reesii to shift from plant to animal substrates are theorized to have led to development of pathogenicity in several Coccidioides and Paracoccidioides species, both of which are highly genetically similar to U.