Most states have an Extension Service. I see that the one in Texas is based out of Texas A&M, and has 250 county offices. One of the services they provide is weed identification.
Nothing on their weeds page is an unambiguous match to your photo, but there are a few likely candidates -- annual ryegrass, johnsongrass, rescuegrass, and a few of the sedges. Once you get seeds or flowers, it'll help narrow it down. The additional photos on each weed's details page might be able to be matched up to your situation with a bit of detective work on your part.
They also provide a weed identification service in which you take in a sample, or e-mail detailed photos.
In Nebraska, they even have a weekly show on public television. If they have that in Texas, maybe you can send in your sample and get a few of your fifteen minutes of fame.