The U.S. Botanic Garden Conservatory will close at 3 p.m. on Tuesday, December 6, due to an official government function. The Conservatory will return to normal hours December 7.
Welwitschia mirabilis grows in isolated communities in the Namib Desert in central Namibia to southern Angola. The plants are seldom found far from the coast, and the distribution coincides with the fog belt. Welwitschia is still somewhat common in its habitat and shows variability, a sign that the species is not near extinction. Although the plant is not endangered, it is protected by law. Rainfall in Welwitschia's natural habitat is erratic and extremely low; often, there are years with no rainfall at all. Welwitschia is ecologically highly specialized and is adapted to grow under these arid conditions in areas that receive regular fog. Welwitschia leaves are formed so that it waters its own roots by collecting condensation, and the leaf surfaces have numerous stomata (microscopicpores) through which condensation is absorbed. Welwitschia also has a long taproot, allowing it to reach water deep underground. Antelope and rhinoceros chew Welwitschia leaves for hydration during times of drought. The cone of the female plant was used as food for people in earlier times; it was eaten raw or baked in hot ashes. The plant's common name is onyanga, which means "onion of the desert."