Gymnopilus subtropicus is a species of agaric fungus in the family Hymenogastraceae.

The genus Gymnopilus was established in 1879 by the Finnish mycologist Petter Adolf Karsten (1834-1917).

Gymnopilus fungi are a diverse group of saprobic mushrooms that typically grow on wood (Hesler, 1969).

They are characterized by their rusty brown spore prints, yellow to orange gills, and, when present, a typically cobwebby and ephemeral partial veil.

G. subtropicus produces medium-sized mushrooms with yellow, fibrillose caps 1.4-4.5 cm broad.

The stipe is 3.5-4 cm long by 3-5 mm thick, enlarged at the base, and yellowish above and brownish below.

It has a cobweb-like partial veil when young, often remaining on the stipe, forming a ring.

G. subtropicus grows on oak and palm logs in subtropical forests across Florida, Mississippi, Louisiana, and Hawaii, fruiting from March to August (Hesler 1969).