Was there any foliage attached to this stem? A foliage photo would be most helpful.

It could be a Gaura.

Gaura lindheimeri has become Oenothera lindheimeri afaik.

"There is a pink variety called Siskiyou Pink which everyone should get because it has a cultivar name which makes it special and desirable."

Huh???

the picture is somewhat not showing the whole flower

just by the flower stem, I would say not Oenothera/ aka Gaura

I have them in my garden, reseeding,

growing through dry summers

their flower stalks are never that "knobbly"

and I think the number of "spurs" is not right

here a pic from my graden

is it in an area where there could pop up some other garden plants or something?

"Oenothera lindheimeri is the only white flowered 'gaura' in Texas, so it must be Oenothera lindheimeri."

that is not really logical,

there could be other white flowering species/genera in Texas, or not?

Actually my mistake, all gaura species in Texas have white flowers at one time or another. That would be Oenothera cineria, sinuosa, simulans, filiformis, gaura, curtiflora, suffratescens, and suffulta. The knotty stem seems to have a couple seed pods that might match Oenothera gaura, curtiflora, or suffrutescens. It looks like an animal or human scraped off some seed pods from the stem giving it the knobby appearance. Can't do much more without adequate foliage and flower photo. If it was a new to gardenweb person asking I could let it slide, but the OP has been submitting for years now, and should know better. A lot of the discussions concerning your questions are often disagreements that would never happen if appropriate photos were submitted at the very start. What's the point of not including foliage pics?? 🤔

“ ….all gaura species in Texas have white flowers at one time or another.”

I’m confused by this, maybe I’m misunderstanding, but my pinks (in Texas) never have had white flowers.

I don’t think the picture asked about here is gaura, but I could certainly be wrong, I’m no expert. I’m intrigued by what it might be.

Just for fun, my sweet ’Whirling Butterflies’ in Texas hell strip just now. I lost another after that freeze. This would usually be 3x this size right now. Not posting a pic of ’Pink Siskiyou’, as it looks awful.

Possibility?

http://www.bio.utexas.edu/courses/bio406d/images/pics/ona/Gaura_suffulta.htm