N. L. Meyer G.  Germishuizen, Flora of Southern Africa (FSA). 2003.

A. L. Stork J.  Lebrun, Enumération des plantes à fleurs d?Afrique tropicale. Geneva : Conservatoire et Jardin Botaniques de la Ville de Geneve, 1991.

J.  Lindley, Introduction to Botany, 4thth ed., vol. 2. London: Longman, Brown, Green and Longmans, 1848, p. 427.

, Flora of Tropical East Africa: Glossary. CRC Press, 2003, p. 368.

V. H.  Heywood, Flowering Plants of the World. Oxford: Oxford University Press, 1978, p. 335.

G. H. M.  Lawrence, An Introduction to Plant Taxonomy. New York: Macmillan Publishing Co. Inc., 1955, p. 179.

B. P. M.  Hyland and Whiffin, T., Australian Tropical Rain Forest Trees: An Interactive Identification System, vol. 1. CSIRO Publications, 1993, p. 303.

M.  Hickey and King, C., Common Families of Flowering Plants. Cambridge: The Press Syndicate of the University of Cambridge, 1997, p. 212.

D.  Oliver, W. Thiselton-Dyer, T., Prain, D., and A. Hill, W., Flora of Tropical Africa, vol. *. 1868.

L. D. L.  E. Smith, Flora of Tropical East Africa. 1966.

J.  Hutchinson and Dalziel, J. M., Flora of West Tropical Africa, vol. 1. 1954.

A. W.  Exell, Fernandes, A., and Wilde, H., Flora Zambesiaca, vol. 2 (Pt.1+2). 1963.

O. A.  Leistner, Seed plants of southern tropical Africa: familes and genera. Pretoria: Southern African Botanical Diversity Network (SABONET), 2005, p. 494.

O. A.  Leistner, Seed plants of southern Africa: families and genera. Pretoria: National Botanical Institute, 2000, p. 775.

M.  Hickey and King, C. J., The Cambridge Illustrated Glossary of Botanical Terms. Cambridge University Press, 2000, p. 208.