Please click on image to ENLARGE and widen view of October 1, 2010, photo of Ludwigia alternifolia on Pinnacle Prairie just west of World Peace Wetland Prairie. Or is it Oenothera fruticosa?
To read more about the plant, please see the following link: seedbox
Another member of evening primrose family is possible seedbox variety.
You may have seen photos of this plant in bloom on this blog or another of my blogs or in my Flickr photo collection earlier this summer.