Flower of an Hour

This is called Fleur de l'heure, "Flower of an Hour".  So maybe it originated in France, like some of my ancestors.  It is so fragile that it can't stand direct sunlight, thus it's name.  I found some growing in the side yard of an abandoned house in Dayton, 20-some years ago.  It is an annual, so it depends upon self-sowing (dropping fully mature, fertile seeds in a suitable and safe location) in my garden/yard for survival, and yet--delicate as it is and precarious as is it's existence--it still makes a volunteer appearance every Summer.