Really not enough to go on at this point - more developed specimen needed, preferably with flowers.

Decussate leaves have the X pattern.

Could it be a lythrum of some sort? I agree with Embothrium that more info is needed to confirm anything.

Is that a square section stem? Puts me in mind of a Scrophularia?? I don't know which ones might be in blackrabs region.

Epilobium?

^^^Well, the leaves look a bit too wide to be Lythrum (Loosestrife)?

^^ Yes, it was a square section stem - I just rechecked it.

But, not sure that it matches Scrophularia umbrosa (Green Figwort)? Looks similar, but not close enough... Not to mention, all the pics of those seem to be from Europe?

^ And I'm also not sure that Epilobium (Willowherb) is found in the US, either?

Yes Epilobium is found in the US.

BONAP is a good resource to check that type of thing. Here is their page on Epilobium, so you can check to see if there are any, either native or introduced, in your area, though I'd say probably not since there are only counties up on the pan handle and in the SW corner of TX that seem to have any.

If the stem is square I don't think it's an Epilobium. And anyhow, it doesn't strike me as such at all. There are lots of Scrophularias and they do have square stems. Can you wait for flowers and come back to us?

I think I've got it: Oenothera.

"Can you wait for flowers and come back to us?"

Sadly, I can't now. It was growing on a relatively steep slope, and I accidentally scraped it out of the ground when my foot slipped into it. :(

^ And hmm, Oenothera looks possible, but its leaves seem to be a little narrower and smoother? Also, its stalk seems a bit thicker and the leaves are spaced at closer intervals along it?

Oenothera doesn't have opposite decussate leaves. The leaf arrangement should to be looked at before the leaf shape because it tends to be consistent throughout a genus, unlike leaf shape.

Oops, you got me there!

Lol, well I guess it's not a problem, since you rogued it out with your foot :)

As well as leaf arrangement, keep that square stem in mind folks, when making suggestions.

OK, I went back and found a bunch more growing in the area. So, here's some more photos:

(The stems are definitely square - which rules out Epilobium.)

And Oenothera has been ruled out too...so what IS this???

Hmm, Ruellia has that sort of floral arrangement at the leaf junction. I'd say though, report back when they flower (which is gonna be soon from the looks of it).

Maybe something in Gentianaceae ?

Chelone?

No on Chelone, the floral buds are quite different (imo)

A flower probably opened. Please run over there asap, the suspense is killing me !!!

Triosteum? Horse Gentian, Feverwort. Looks like there are a couple species in Texas. Don't know about the square stems though.

Can't find any mention of square stems, but the stems of Triosteum are hollow. Seeing some opened FLOWERS would help immensely. No pressure! I'll wait.

Haha, OK the suspense is over...although you might find this rather anticlimactic..

So, its flowers basically look like tiny condoms, maybe ~1/2" long or so?

It doesn't even seem like these odd little flowers actually open before they fall off - so I don't even see how they are supposed to get pollinated? Not to mention, nor do I see any of the basic structures of flowers in them...so they are quite unusual, indeed!

But, they should really help determine a positive ID, now!?

Ruellia flowers are gone by the afternoon. What time did you photograph ? Did you look for spent blooms on ground?

They must have been pollinated because there are numerous seed pods visible.

^^ No, I did not see any Ruellia flowers anywhere. Although it had also recently rained, so it is possible (albeit unlikely) that any could have gotten washed away downslope... But that would not explain why there are tiny flowers on there now? I mean, clearly, those are the plant's actual flowers, odd as they are?

.

Hey Devin,you've got punctuation without words this time. I prefer it the other way . It's all good! I still have no clue as to what it could be, even with the new pics. The truth is out there !

Ok, I've been lurking on this thread for a few days and I really think that a couple of people (carol and weedwoman) got it right, it's a gentian, probably bottle gentian since the flowers don't open, the leaf arrangement is perfect and the flowers form in the leaf axils, the flower color can range from blue to pink or white. The flowers are smaller than one might expect but that could just be natural variation, here is a link to the article that convinced me: https://www.minnesotawildflowers.info/flower/bottle-gentian

also note how each pair of leaves going up the stem of the gentian changes direction, criss crossing, if you will... lol

No Blake, those are the remnants of flowers that fell, I'm pretty sure. Not the actual flowers.

If you look at the unopened buds you see petals, they're nowhere to be seen on the remnants.

I am not convinced that it's bottle gentian, Gentiana andrewsii. The leaves don't look quite right, the tuft of leaves at the top of the stem also don't agree with photos or my memory of this plant, and to the best of my memory, G. andrewsii doesn't drop its flowers as cleanly as this plant.

I also went out to the garden and checked another species of gentian, and it doesn't have square stems.

it may not be andrewsii but g. saponaria is native to Texas and has mostly closed flowers too, and some gentians have square stems so not sure on the specific species but I'm pretty positive its a gentian, anyway that's my story and I'm sticking to it

Ok, so I don't know much at all about Gentana, and have zero experience growing them. Do bottle Gentians have condomlike flowers? I thought they never fully opened, so would they have spent petals laying about? Are any species known to have square stems? There aren't any species of Gentian in Texas that even look close to this plant. Other families in the Gentianales are Rubiaceae,Loganaceae, Gelsemiaceae, and Apocynaceae. Gelsemium is made up of large flowered species with the ones occurring in Texas bearing no resemblance. I haven't checked every species of Gentian growing in the U.S. outside of Texas, but all of the species I've looked at so far also bear no resemblance.

Well even the species that don't open are not fused together, so insects can still get in to pollinate, I believe andrewsii (bottle gentian) is only pollinated by bumblebees because they are the only insect heavy enough to open the ends of the blossom and get inside. Some species do seem to have square stems as well but I haven't found one that has both square stems and closed flowers. There are some fairly obscure species that are not described very well, online anyway, or maybe environmental conditions have altered the phenotype of this particular population in some way or caused the plant to abort its flowers before maturity. I'm leaning toward gentiana saponaria but it doesn't fit exactly, and there is some evidence that gentians are a fairly promiscuous genus so maybe a hybrid? Or maybe it's a new species and we should call it Fairy Condom Gentian, that would be kind of ironic, I guess....

Blakrab, maybe you could cut one down and take it to your local extension office for an ID

Very interesting Thanks for the info Andrea.

It's alarming to discover that fairies are practicing birth control. There's far too few buzzing around my flowers as is!

Jay hehe I was commenting just to follow because I wanted to know but have never seen anything like it haha I love ur last comment !!!!:)

I wonder if it could be related to the Sesame (Sesamum indicum) plant, which bears some striking similarities?

"Sesame is a strong, slender annual growing to about 3 – 6 feet tall with
slender, dark-green leaves and inch-long trumpet-shaped pale pink to
light purple flowers which flow along its square stem."

Ok, so dbarron wins the prize!!! Took nearly 10 months to verify it...but better late than never!

As I saw these same plants again, but this time while actually in full bloom!

So, this is Ruellia strepens (Limestone Wild Petunia)! The fact that there's so many varieties made it confusing... And I guess after the flowers drop off, they leave those tiny "condom" seed sacs? Which was even more confusing!

But anyhow, now this cold case can finally be PUT TO REST!!! B)

Nope. No purple flowers. I have a huge patch of this. Inconspicuous white flowers. I have two other ruellias, Mexican petunia and a shorter brighter green- very similar purple

flowers. This may be ruellia- it does propagate by underground runners, but that tiny white flower at the leaf axil is it.