An old s****y mystery

A few years ago I was walking with a friend of mine along the trail towards the forest where I work. Along the way I happened to spot some scat in the middle of the trail. It was tapered and long, fairly fat, and had some seeds in it. The scat appeared to have come from a Coyote but I was at a loss as for what kind of plant the seeds had come from. I looked up a couple of books I have which have a few photographs of seeds but never found an image of a seed which looked right. The mystery haunted me.