Those fine scales on the cap (pileus) seem to indicate it may be and Agaricus sp. Any photos of the underside of the fungus, or did you notice the colour of the gills (lamellae)?
Ooops - sorry I missed those. Yes, those structures are the gills (lamellae) which are the spore bearing parts of the fungus and that colour is typical of this genus as the spores mature. This fungus belongs to the same genus as some of the mushrooms you see in the shops. When they are young the gills will usually be a very pale pink. As the spores mature the gills will become darker with those maturing spores. You can take a spore print by cutting of the cap (pileus) of the fungus, put it on some white paper and cover it so the air currents don't blow the spores away. Then I find with this genus usually within a few hours you will have a print. Even within that one genus I've noticed different species have slightly different tones of colour. Some genera you may have to leave the cap covered overnight, and if the insects haven't turned it to slosh, you should get a print. Different genera will have different coloured spores.