Oak roll rims are mushrooms which often (but not invariably) grow near to oak trees.
They have a dull brown cap, and yellower gills, stems and flesh. As they come up they have a domed cap, but as they grow older the rim rises above the centre.
Pictures taken over the course of four days showing the developments of a group of mushrooms growing on a garden path.
At first the mushrooms had a tan cap, with a paler stem.
Later the cap faded to a duller pale brown, exaggerated here by the changing lighting conditions.
Notice the holes in the caps where slugs have been nibbling. Tiny slugs are on the caps in some of the pictures.
Small new mushrooms, complete with the stronger cap colour, continued to pop up in the middle of the patch.
The path was covered in wood mulch to suppress weeds. It is possible that the mushrooms had been brought in with this mulch.
The mushrooms were probably bonnet mycenae, a common fungus,