Unusual Flower (I thought it was wheat)

This little flower caught my eye as I was emptying my kitchen compost into our large city collection bin. I've seen it before, and I thought it was wheat, but as I looked more closely, I saw some beautiful little yellow flowers inside the beautiful dark brown, wheat-like "oats" at the top of the grass. So, I suppose it isn't grass at all! :)

It's only about 3" to 4" high - so it pays to bend down occasionally and see if you can find some hard-to-notice, but still beautiful, wildflowers!