Mystery wildflower

My neighbor has a beautiful field full of wildflowers -- some that came to her with the property and some that she has lovingly sown over the last few years.

And out in the middle of the field is this one, tall plant.

I have no idea what it is, and a flip through my book of Texas wildflowers didn't turn up anything that I thought fit quite right.

Do you know what it is?

It's growing in rock and has little to no water since we are in a drought and the field has no irrigation of any sort.

She'd really like to know -- can you help Maria name this plant?

On a side note:

My garden and my weeds are overgrowing and I've neglected my blogging for a while because my Mom's been in the hospital twice in the last few weeks and I've been there with her. We got a good post-surgical prognosis today, so she's going to be on the mend soon.

And I'll be back in due time.