Pholiota ventricosa Earle (1902) Gymnopilus ventricosus, commonly known as the jumbo gym,[2] is a species of mushroom in the family Hymenogastraceae.

It was first described from the Stanford University campus by Franklin Sumner Earle as Pholiota ventricosa in 1902.

The cap is 5 to 30 cm (2 to 11+3⁄4 in) or larger in diameter.

[3][4][5][6][7] The stalk is thick and bulbous, with a membranous ring.

[5] This species contains no psilocybin, and is considered inedible; it is very bitter.