Large fungi with crusty brown and cream patterned looking cap about the size of a cricket ball. The gills were a pale brown colour but as the fungi matures the cap flattens out to a large disc and the gills turn very dark brown to black.
There are many unidentified species in the Agaricus genus. I was a little unsure initially as to which species this is as the mushroom's form is a little atypical with its drooping cap. The A. augustus is a large species and can be 200mm across and sometimes larger. The changes in the colour of the immature gills to the very dark brown to black of the mature gills is typical of this genus as the spores mature.