This desert plant grows only two leaves in its life, and may live 2,000 years.
Welwitschia mirabilis grows in the Namib Desert, where rain can be almost non-existent. It produces just two leaves, which never fall but keep growing from the base for its entire life, weathering into tattered ribbons up to 4 metres long. The oldest plants may be around 2,000 years old.
When the Austrian botanist Friedrich Welwitsch came across the plant in Angola in 1859, he wrote that he could do nothing but kneel and gaze at it, half afraid a touch would prove it imaginary. Joseph Dalton Hooker formally described it and asked to name it after Welwitsch, who agreed. Its Afrikaans name, tweeblaarkanniedood, means 'two leaves, can't die'. It is the only species in its genus, family and order, and one of just three surviving genera of gnetophytes, a small group of cone-bearing seed plants.
After germinating, a seedling produces two temporary seed leaves, then two permanent ones. Soon afterwards the growing tip of the stem dies, and growth moves to the rim of a woody, disc-shaped crown, which keeps extending the two leaves from their base for the rest of the plant's life. Wind and weather split them into ribbons, so an old plant looks like a heap of shredded foliage. The crown can reach a metre across; the largest known individual is 2.77 metres in diameter. It was once thought to be a kind of 'giant seedling', but its anatomy suggests instead that it effectively lost its head early in life.
It grows along a belt more than 1,000 kilometres long in Namibia and Angola, where the coast gets almost no rain and inland areas less than 100 millimetres a year. Populations cluster along seasonal watercourses, suggesting it relies on groundwater as well as fog. Plants are male or female, and their cones make nectar that attracts flies and other insects, which carry pollen between them. Its genome, sequenced in 2021, bears traces of bursts of 'jumping gene' activity likely triggered by stress during recent periods of intense drought.
The species is not currently endangered, and international trade is controlled under CITES. Its long life helps it ride out bad years for breeding, but recruitment is low: a fungus infects female cones and ruins many seeds, and plants suffer from grazing by zebras, rhinos and livestock, from off-road vehicles and from collectors. In Angola, grimly, landmines left from the civil war have helped protect it. It appears on Namibia's coat of arms, growing from a sand dune.
Source: Wikipedia — Welwitschia · Text summarised from Wikipedia (CC BY-SA 4.0)
