This inkcap mushroom is gently deliquescing – disintegrating from the rim to release its spores.
Boletes are a group of species of mushroom which have approximately a classic toadstool shape, but the spore-dispensing bodies under the cap are pores rather than gills.
The specimen above shows the pores to the extent they can be seen without picking the fungus,
Side view of another fruiting body, somewhat nibbled at the sides. Again this is about as much of the underside of the cap as can be seen without picking. The front rim of the top of the cap is showing the beginning of the cracking process which gives this species its name.
Finally, below, view from above of yet another fruiting body, this one forming the landing platform for a fly.
All the mushrooms pictured here were part of a scatter of perhaps 60 to 80 which were standing along a grassy verge. Others had been kicked over as often happens to noticeable toadstools. Had these been undisturbed there would probably have been over a hundred altogether. It is quite possible that all of these fruiting bodies come from a single underground fungus.