Welwitschia mirabilis has divided opinions more than most plants. Nineteenth-century botanists found it ugly, even grotesque. Modern researchers see something else: a plant that has worked out how to live in one of the driest places on Earth and keeps going for centuries while doing it. It has only two leaves. Everything else about its story follows from this discovery.
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| Welwitschia mirabilis is an unusual desert plant native to Namibia, known for its long leaves and remarkable longevity. |
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Welwitschia mirabilis is the sole species in its genus, and that genus is the only one in the family Welwitschiaceae. Botanists group it with the gnetophytes, a small, odd branch of the gymnosperms that also includes Gnetum and Ephedra. Fossil evidence links it to related plants, which is why people often call it a living fossil, though that’s an informal label rather than a scientific term. Ginkgo trees, such as those lining Tokyo’s Meiji Jingu Gaien avenue, get the same nickname.
The plant became known to science in the middle of the nineteenth century. The Austrian physician and botanist Friedrich Welwitsch documented it in Angola in 1859. He wanted to call it Tumboa, after a local name, and the plant is still sometimes called the tree tumbo. Joseph Hooker at Kew had other ideas and named it Welwitschia in Welwitsch’s honour, with mirabilis meaning 'wonderful' or 'extraordinary' in Latin. Hooker himself is said to have called it the ugliest plant in the world.
Its appearance is due to its body plan. The plant grows from a short, woody crown that sits close to the ground. Two leaves sprout from it in the seedling stage, and they never stop growing. Wind and sand shred the older ends into long ribbons, so a mature plant looks like a heap of leaves when it’s really just a pair. At the base, each leaf can be about 90 centimetres wide. The Afrikaans name, tweeblaarkanniedood, means roughly “two leaves, can’t die.”
Plants are either male or female, and both carry cones. Estimates for the oldest individuals run from around a thousand years to as much as two thousand. Where it lives matters just as much. Welwitschia mirabilis grows in a narrow strip from the Bentiaba River in southern Angola down to the Kuiseb River in Namibia, and no more than about 100 kilometres inland. Rain is scarce there, so the plant relies on sea fog rolling in from the Atlantic. Its leaf pores open at night to take in moist air and close once the day heats up. A deep taproot reaches underground water as well, which is why plants often line dry riverbeds and trace watercourses you can’t see.
Each plant also works like a tiny island. Reptiles and small mammals use its shade, and bees, wasps and flies visit for nectar. A black-spotted insect, the Welwitschia bug (Probergrothius angolensis), is nearly always present and is found nowhere else. The species isn’t under immediate threat, and populations are large. Still, its position isn’t secure. Growth and recruitment are slow, seeds need several days of rain to germinate, and the whole range sits within one habitat type, which leaves it exposed to overgrazing and disease.
First Image Credit: Wikimedia Commons
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| A Welwitschia mirabilis plant in Namibia. Its unusual shape and long leaves make it one of the most distinctive plants of the Namib Desert. |
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| A male Welwitschia mirabilis in Namibia’s Namib Desert. The unusual desert plant is known for its long lifespan and distinctive flowering structures. |
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| A Welwitschia mirabilis specimen at Garfield Park Conservatory. This unusual plant is native to the Namib Desert and is known for its distinctive leaves and remarkable longevity. |
Welwitschia mirabilis earns the second half of its name. Two leaves, a deep root, and a steady supply of fog are enough to keep it alive for centuries in one of the harshest deserts anywhere. Another desert curiosity worth reading about is Dunhuang’s crescent-shaped Lake Yueyaquan.
Sources: Kew, Welwitschia mirabilis (tree tumbo) · Wikipedia, Welwitschia · BBC Discover Wildlife, Welwitschia mirabilis · Wikipedia, Friedrich Welwitsch
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