Gymnopilus ventricosus

Gymnopilus ventricosus, commonly known as the jumbo gym, 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.

Description
The cap is 7 to 8 cm or larger in diameter. The stalk is thick and bulbous, with a membranous ring. This species contains no psilocybin, and is considered inedible.