Distribution
Welwitschia mirabilis © Sara&Joachim on Flickr, Creative Commons Attribution-Share Alike 2.0 Generic
© Thomas Schoch, Creative Commons Attribution-Share Alike 3.0 Unported
Welwitschia mirabilis is limited in distribution to the desert or desert margin along the south-west coast of Africa. This land strip is about 1000 kilometres long and stretches from the Kuiseb River, just south of Walvis Bay in Namibia (latitude 20–24°S), to the Nicolau River in Angola (latitude 15–16°S).
While some dispersed populations are found 200 kilometres inland, the majority of specimens are situated within 80 kilometres of the coast.
Ecology
Based on this plant’s distribution, it is thought that fog is an important source of water.
Its habitat is extremely arid - annual rainfall is 10–100mm during the summer, but some years there is no rain at all.
This plant grows on gravel or rocky ground and has a long taproot to take underground water. The fog contributes with about 50mm dew a year.
This plant can stand extreme temperature fluctuations between 7°C at night up to 50°C during the day.
