| Parent | Category | Figures | |
|---|---|---|---|
| 1 | Houstonia | caerulea | 1112 |
| 2 | Houstonia | pusilla | 593 |
| 3 | Houstonia | purpurea | 193 |
| 4 | Houstonia | longifolia | 157 |
| 5 | Houstonia | serpyllifolia | 79 |
| 6 | Houstonia | procumbens | 75 |
| 7 | Houstonia | acerosa | 48 |
| 8 | Houstonia | wrightii | 45 |
| 9 | Houstonia | micrantha | 38 |
| 10 | Houstonia | rubra | 36 |
| 11 | Houstonia | rosea | 24 |
| 12 | Houstonia | canadensis | 21 |
| 13 | Houstonia | humifusa | 5 |
| 14 | Houstonia | subviscosa | 1 |