Unknown spotting

Description:

A mushroom with a very rough textured dark purplish-brown cap about 30mm wide. The cap had an umbo and seemed to have regular folds at the margin. There were no corresponding folds on the under surface; the gills evenly spaced and the same colour as the cap. The stipe was smooth and a purplish white.

Habitat:

growing in a grassy verge in a nature reserve. Not immediately under any particular tree.

Notes:

I thought I was looking at a withered mushroom but this one was certainly still fresh - just sturdy and tough-looking. Will look for an ID