Opuntiaaustrina makes a small bush. Mature plants typically have a well-defined trunk and grow to 3-ft tall, but smaller plants are common. It grows in disturbed areas (e.g., cow pastures) or in undisturbed areas (e.g., pine hummocks). Britton and Rose reported that O.austrina occurs in southern FL. Cladodes may be 2- to 5-inches long. Areoles may have a single major spine. O.austrinahas been proposed to be the same taxon as O.ammophila and O.polycarpa. We accept it as a stand alone taxon. See the original description. Opuntiaaustrina is tetraploid.