Need ID on flowering tree

Need ID on flowering tree

I saw one of these growing near an apartment building near Rice University here a couple of years ago, and picked off a couple of seed pods but misplaced them. So, this afternoon I was in the area and drove by the spot only to discover they'd been cut down, and a plumeria in a whiskey barrel was sitting in their place! A few shoots were coming up from one of the stumps, so I jumped out of the car and pulled a couple of the shoots off hoping to root them in something. I'm not sure if this is the same tree, but it looks similar. I found it growing at a restaurant nearby. Pics taken from a vehicle. I wish I could have gotten a better closeup! It reminds me of a mesquite tree, only with.. flowers instead of thorns. This brings me to a question about propagating via cuttings. Is there an optimal size for a cutting? I've added some pictures of the cuttings I've taken. It doesn't look as if they're from the same plant, but the original plant is gone so it may be a few years before I find out... I think the flowers are more cone shaped, but they also have the same brilliant red stamens. EDIT: Added photos of the cuttings I've taken.
Photos From my Garden

Photos From my Garden

The room of Baerana and Nibbler

The room of Baerana and Nibbler

Jewels of Opar and Eggplant

Jewels of Opar and Eggplant

GardenshowTime!

GardenshowTime!

re-planting hydrangeas?

re-planting hydrangeas?

The big project to date (almost)

The big project to date (almost)