yellow wildflower

Love this beautiful little wildflower, which is blooming in CT, even in mowed areas, where it seems to pop back up after mowing. Flowers are pea-like and a really saturated, velvety yellow. With them in this plastic cupis some spearmint. I have, somewhere in the stuff I've been packing up from my mother-in-law's apartment, the perfect vase for them, but, at this point, I have no idea which box it is in!