Brambles, probably blackberry, framed by bits and pieces of prairie grass.
The mosaic (calico) nature of the color change in the bramble leaves is unusual, but not rare.
A note on my composition. I did try to position the camera to get more separation between the twisted blade of grass and the green leaf, but my shadow kept intruding when I did so. You take what you can get.
Dow Prairie area of Nichols Arboretum
Ann Arbor, Michigan
Taken October 10, 2017