| Rubiaceae | |
Psychotria hombroniana var. canfieldiae
| Fosberg | Allertonia 6: 253 | 1991 |
| Rubiaceae | |
Psychotria hombroniana var. carolinensis
| (Valeton) ined. | | |
| Rubiaceae | |
Psychotria hombroniana var. hirtella
| (Valeton) Fosberg | Smithsonian Contr. Bot. 45: 29 | 1980 |
| Rubiaceae | |
Psychotria hombroniana var. hombroniana
| | | |
| Rubiaceae | |
Psychotria hombroniana var. kusaiensis
| (Kaneh.) Fosberg | Smithsonian Contr. Bot. 45: 29 | 1980 |
| Rubiaceae | |
Psychotria hombroniana var. ladronica
| (Hosok.) Fosberg | Allertonia 6: 255 | 1991 |
| Rubiaceae | |
Psychotria hombroniana var. malaspinae
| (Merr.) Fosberg | Smithsonian Contr. Bot. 45: 29 | 1980 |
| Rubiaceae | |
Psychotria hombroniana var. mariannensis
| (Kaneh.) Fosberg | Allertonia 6: 255 | 1991 |
| Rubiaceae | |
Psychotria hombroniana var. peliliuensis
| Fosberg | Allertonia 6: 255 | 1991 |
| Rubiaceae | ** |
Psychotria hombroniana var. squarrosa
| (Valeton) Fosberg | Smithsonian Contr. Bot. 45: 29 | 1980 |