"Before the phrase “mesquite-grilled” became a common descriptor on hoity-toity menus of restaurants trying to prove their Texas bona fides, and before backyard cooks bought mesquite chips by the pound to add an “authentic smokehouse” flavor to their meat, the mesquite was a scraggly tree that people in the Southwest considered a nuisance."

Source: http://www.tmbbq.com/smoking-with-mesquite/