Something in Amaranthaceae. Maybe an Alternanthera. Bonap reports several species present in TX:

http://bonap.net/Napa/TaxonMaps/Genus/County/Alternanthera

I gave no idea what this is but don’t see anything particularly Amaranthaceae about it. I’d plump for Asteraceae if anything.

It does remind me of my Mexican Sunflower plants, Tithonia rotundifolia, in winter.

I’ve been gathering seeds every day from them. But I don’t know if that’s what this is, mine still have quite a bit of green on them. They aren’t completely dormant yet, our weather has been mild up here (D/FW).

You could probably try piecing together leaf remains on a piece of white paper, so we can at least have a vague idea of their shape? Also, a picture of the seeds can most enlightening?