The 44 plants described in this guide represent an estimated 75% of the overall brush biomass of the South Texas ecological region, excluding the lower Rio Grande Valley. This plant identification field guide is designed by the authors to assist landowners, managers, biologists, ecologists, hunters, and anyone else interested in the identification of woody vegetation in South Texas. Their objective is to produce an informative, easy-to-use plant-identification field guide, providing the most current knowledge and nutritional information available on selected woody plants and cacti important to wildlife and livestock in South Texas. The plants are grouped into thorned and thornless categories and alphabetized by family. Distinguishing characteristics have been italicized for easy reference. Similar species are also noted. In this guide, plants are not ranked by importance because their value to animals can differ from ranch to ranch, depending on the plant's availability and the ranch's location, soil type, and land management practices. In case a plant is not found in this guide or more information is desired, a list of additional references is included.