At last! I can prove knowing about Plant Families has a use! Phlox is a member of the Polemoniaceae, and has five petals. This flower has four petals, so it isn't Phlox. This flower has four petals in a cross shape, so it's a member of the old Cruciferae (new name, Brassicaceae - flowers like cabbage flowers). I think it's Honesty (Lunaria annua).
It now has large flat roundish seed pods coming on (right now they are green), isn't Lunaria "money plant"? I have quite a few of these, and had it on my want list! (Poppysue sent me seed from a varigated variety). I had never seen one bloom before, but always liked the dried seed pods. Thanks everyone! Julie