Yellow Star Grass

This little lovely was very difficult to identify. I thought it was Yellow Star Grass, but when I looked in my guides, all their photos and drawings show a flower with three petals and three sepal...... this does not have three and three .... it has four petals and four sepals????? I asked those I know who might shed some light on the mystery and no one knew. Finally I emailed the botanist at the Hitchcock Center in Amherst and he said that it just must be a variant of the three petal and three sepal Yellow Star Grass. Now my question..... will this variant  pass on this trait in it's seeds and next year reveal more of these variants???? We will just have to wait and see.  This flower is not only unique but it is independent also, usually  it is pollinated by certain bees, but if they fail in their job, this little flower will close up, and the radiating stamen with pollen laden anthers will squeeze close enough to the stigma to pollinate itself.

Where I found it : In a field