Wowzers, Folks!
Ya'll hit the nail on the head! Definitely Ludwigia. And I'm inclined to go with L. decurrens due to the elongated seed pod as well as the fact they are longer and square rather than short and "cube like" as described for L. alternafolia. (And darn, I always liked saying "bonariensis", it makes me feel smart, but alas...it doesn't look like that one.) But I'm easy and can now add 'decurrens' to my vocabulary!)
I just took these pics, hopefully showing the decurrent leaf attachment and I also cut the top off one of the seed pods to show its squareness.
Thanks a gajillion everyone!
Best to you and yours,
Shoe
