Spotting

This is clearly a mushroom belonging to the Agaricus species. The fact that it grows in a forest (as I see from the picture) makes me think of the Agaricus moshrooms that grow in forests: A. Silvicola and A. Sivaticus, but it doesn't look like any of them. The short stem makes me think about A. Bitorquis... but it can be just the common field mushroom (A. Campestris) just grwoing in an unusual spot.