Thank you! You're right, it is one of the Lysimachia family of plants. I'm thinking either Lysimachia lanceolata or Lysimachia quadrifolia L.
Hmm. The Lysimachia is different. Here are a couple close-ups. The leaves form a whorl of 4. The stems of the flowers or fruit or whatever they...
So far tonight I've managed to identify 2 out of 3 plants that I was looking for. Either I'm getting tired of searching, or I'm just not...