This little gem appeared in the middle of our yard last year. It's all of about 7" high and graced us with its first bloom just a few days ago. Unfortunately, a squirrel or something got it and ripped all the petals off within a few hours of taking this photo. (It's in a tomato cage so it doesn't get accidently mowed over like last year)
I'm also trying to figure out how it got into my yard. Not that I'm complaining. :)
Dawn