Bruyns, P.V. 2002. Monograph of Orbea and Ballyanthus (Apocynaceae-Asclepiadoideae-Ceropegieae). Systematic Botany Monographs 63:1-196.
Bruyns, P.V. 2005. Stapeliads of southern Africa and Madagascar. (Vol. 1, pp. 1-330). Umdaus Press, Pretoria.
Hilton-Taylor, C. 1996. Red data list of southern African plants. Strelitzia 4. South African National Botanical Institute, Pretoria.
Leach, L.C. 1978. A contribution towards a new classification of Stapelieae (Asclepiadaceae) with a preliminary review of Orbea Haw., and descriptions of three new genera. In: Excelsa Taxonomic Series 1, The Aloe, Cactus and Succulent Society, Rhodesia.
Raimondo, D., von Staden, L., Foden, W., Victor, J.E., Helme, N.A., Turner, R.C., Kamundi, D.A. and Manyama, P.A. 2009. Red List of South African Plants. Strelitzia 25. South African National Biodiversity Institute, Pretoria.
Scott-Shaw, C.R. 1999. Rare and threatened plants of KwaZulu-Natal and neighbouring regions. KwaZulu-Natal Nature Conservation Service, Pietermaritzburg.
|