These two pictures were sent to me from one of our local master gardeners. She said she didn't plant it. Any ideas?

It reminds me of Oenethera...

Sure looks like Oenothera to me. At first I thought maybe Oenothera biennis but there's another yellow flowering one that I think is native in Texas, O. texensis: http://www.google.com/search?q...

Thanks Lin, I'm sending you an acorn as a thanks for the ID.

Dave, thank you for another Acorn! I'm sending one right back to you too! You knew it was Oenothera, and I know it is too ... just not sure which one!

Those plants grow in our pond. I always thought they were some sort of water plant, but this year most of the pond dried up and they are happily rooted in dry earth.
When the pond is full, they grow and bloom just floating near the edge.

oops, disregard. I googled images, and my yellow flower is a Ludwigia. Close, but no cigar. I've never seen a Oenethera with such small blooms. Ours are 3" at least. The master gardener will know for sure next year when she has a full crop come up! I wonder if that one opens in the evening or all day? My large flowered ones open around 6 pm, all of them within a minute of each other.

CindiKS said:all of them within a minute of each other.

Isn't that interesting? They sound like beautiful plants!

I think the plant in question could be this one Ludwigia octovalvis ;
http://wildflower.org/plants/r...
Josephine.

Not sure about the octovalvis part, but I thought it was Ludwigia myself.

Those photos certainly are a perfect match! I'll pass this along to the MG in my group who sent it to me - thank you!

You are welcome, glad to be able to help