Agaricus fuscofibrillosus is a mushroom in the family Agaricaceae. It has a medium to dark brown cap up to 6 cm (2.4 in) in diameter with brownish fibrillose scales that darken in age. The tightly-packed gills are initially cream colored before becoming pinkish, lilac-gray, and finally brownish as the spores mature. The stout stem is enlarged to bulbous at the base which has one or more brown bands, and a white, membranous ring. The mushroom is edible, and has a pleasant odor similar to button mushrooms, and tastes similar to Agaricus bisporus when cooked.