Ex Situ Horticulture of Welwitschia mirabilis

Abstract

Welwitschia mirabilis Hook.f. occurs in the Namib Desert of Namibia and Angola. It survives on fog which condenses on its leaves, supplemented by flooding every six to ten years. The seeds contain germination-inhibiting alkaloids which must be washed out by rainfall before germination can take place. Many seeds are also infected with the fungus Aspergillus niger which causes high levels of mortality in newly germinated seeds. A strategy for the control of this black smut fungus is described along with techniques for seed sowing and cultivation.