Grows on my lawn all the time: leaf: http://www.flickr.com/photos/76284694@N02/8718556147/in/photostream http://www.flickr.com/photos/76284694@N02/8719670794/in/photostream whole plant: http://www.flickr.com/photos/76284694@N02/8718554387/in/photostream Not the best pictures, because it was a sunny day.
Looks like it could be an Ox eye Daisy. Will have Shasta daisy-type flowers in the summer, but much smaller.