Out in the Tamaulipan thornscrub of South Texas, Mario Garza has spent years looking for something sacred. To the untrained eye, the ranchland he visits might seem unremarkable, or even hostile — a wide expanse of mesquite and huisache thickets littered with rattlesnakes and tasajillo spines, among other natural hazards. But Garza sees it differently. This is the land of his ancestors, the Coahuiltecans, who inhabited this region for centuries, and who knew what the limestone-rich soil had to offer them. To him, the landscape is dotted with Lophophora williamsii — a small, bluish-green cactus better known as peyote.