believe this is Cirsium arvense, one of many types of purple thistle. (It could also be Cirsium altissium).
For a moment, I thought these were a flower I had never seen. Most thisles grow upright, but after strong winds and rain, this outcrop was bent over.
For a different variety of purple thistle see: http://idarkansas.blogspot.com/2008/05/purple-thistle.html
Info to be added
All pics, mid September 2008