| Houstonia angustifolia Pursh | Houstonia purpurea L. |
| Houstonia grandiflora Raf. | Houstonia caerulea L. |
| Houstonia humifusa Hemsl. | Houstonia wrightii A.Gray |
| Houstonia linnaei Michx. | Houstonia caerulea L. |
| Houstonia macrosepala Nutt. | Houstonia purpurea L. |
| Houstonia purpurea longifolia (Gaertn.) A.Gray | Houstonia longifolia Gaertn. |
| Houstonia saxicola Eastw. | Houstonia rubra Cav. |
| Houstonia serpyllifolia alba Alexander | Houstonia serpyllifolia Michx. |
| Houstonia tenella Pursh | Houstonia serpyllifolia Michx. |