| Author | Title | Journal/publisher | Literature ref. no. |
| Plowes, D.C.H. (1993) | The taxonomy of the Genera Pachycymbium Leach and Angolluma Munster (Stapelieae: Asclepiadaceae) | Excelsa 16 103-123 | 896 |
Note that the process of capturing references from species to the literature and the reverse may be incomplete.
| Species found: 4 |
| Australluma ubomboensis |
| Orbea lugardii |
| Orbea rogersii |
| Orbea schweinfurthii |