Namib. A seemingly desolate expanse of sand and rock, where the relentless sun beats down upon a hostile landscape that stretches out like an endless stony silica canvas. This coastal desert—considered, perhaps, the world's oldest—extends up to 1,200 miles along the Atlantic coast of Africa from Angola’s Namibe province, southwards across Namibia to the Olifants River in the Western Cape province of South Africa. And apart from the usual suspects, nothing much—you’d presume—can be found here, right? Not quite! There exists a plant so extraordinary that it challenges conventional botanical norms. The Welwitschia mirabilis—often simply called Welwitschia—is a living fossil straight from the Jurassic era. It isn't just another desert plant; it is a living paradox. Its mere existence defies the understanding of plant biology. Its longevity surpasses almost all other plants. And its resilience is well… nothing short of astounding.
Welwitschia Mirabilis: A Botanical Anomaly?
Perhaps, the most resistant—and resilient—plant on earth, Welwitschia mirabilis is a member of the family Welwitschiaceae family, a small group of gymnosperms that includes only this single genus. It has no known close botanical relatives. Other gymnosperms include plants like conifers, ginkgo, and cycads. Welwitschia’s name is derived from Friedrich Welwitsch, the Austrian botanist who first encountered it in 1859 and was, quite, dumbfounded when he first saw it! The species name mirabilis reflects its remarkable nature, meaning 'marvelous' or 'wonderful' in Latin. However, the plant is, also, commonly called tumboa, n'tumbo, tweeblaarkanniedood, !kharos, nyanka, and khurub in different local languages. Tree tumbo is, also, another name widely used for this plant.
Not exactly one of the most attractive plants around, Welwitschia is often described as one of the most bizarre and fascinating plants on earth. A relic of the Jurassic gymnosperm era, it has persisted in isolation, adapting to the increasingly arid conditions that claimed its relatives. Its characteristics make it distinctively unique from any other known species. Because it is so different from other gymnosperms, this plant was classified in its own family in a small order of gymnosperms called the Gnetales (the order Gnetophyta). It shares this order with two other families each containing one genus: The Gnetaceae (Gnetum) and the Ephedraceae (Ephedra). All three genera can stand by themselves, and the relationship between them remains remote. But Welwitschia is the remotest of them all.
The plant has, quite, an utterly distinctive morphology. Unlike virtually all other plants, a mature Welwitschia mirabilis consists of just two permanent leaves, a stem base, and an extensive root system. These leaves, the only ones it produces throughout its entire lifespan, are broad, strap-shaped, and leathery, lying flat on the ground. They continuously grow from the plant’s base, and over time become torn and tattered, giving the appearance of multiple leaves. Their deeply divided and frayed nature is mainly due to being battered by the relentless desert winds and other elements. But even then, they can reach impressive lengths of several meters, forming a sprawling rosette that embraces the ground. The ends of these leaves often become dry and dead-looking. The plant's stem, short and thick, is largely subterranean, with only a small portion visible above the surface. This unusual structure is a key adaptation to its harsh habitat.
Welwitschia is dioecious, meaning that individual plants are either male or female. Male plants produce small, salmon-colored cones, while female plants produce larger, blue-green cones. Both types of cones produce a sweet, nectar-like substance to attract pollinators, which are believed to be insects, possibly wasps. Pollination occurs over an extended period, encouraging cross-pollination. Seeds are dispersed by wind in the spring after the female cone disintegrates. The seeds are large, with a papery wing, and remain viable for several years. However, germination requires sustained rainfall, which is rare in the Namib Desert, leading to synchronized germination events in some areas. Even more, Welwitschia’s growth after germination is unique; the apical growth point of the stem stops early, causing it to grow outward and upward, resulting in its characteristic shape. This growth pattern is unlike any other plant, contributing to its classification as a relic from the Jurassic period.
Adapted to Life on the Edge
Welwitschia mirabilis is believed to have evolved around the same time as the dinosaurs, approximately 200 million years ago, and due to its unique adaptations, has been able to survive in the desert landscape for all those years. This ancient plant is endemic to the coastal foggy deserts of the region from the Kuiseb River in central Namibia to Mossamedes in Namibe province, southwestern Angola. The area is characterized by extreme aridity, intense solar radiation, and scorching temperatures since it receives minimal rainfall. Water is, as a result, a precious and limiting resource. However, the coastal fogs that roll in from the Atlantic Ocean provide a vital source of moisture, which the plant ingeniously exploits.
The plant's distribution is restricted to a narrow coastal strip where these fogs are prevalent, typically within 100 to 150 kilometers (90 miles) of the ocean coast. It thrives in areas where this regular fog provides essential moisture, often near dry riverbeds, or rocky outcrops where underground water is somehow accessible. Its distribution, basically, coincides with the fog belt, where the cold Benguela Current meets the hot desert air, creating the dense fog that contributes significantly to its water intake. The plant is remarkably well-adapted to these conditions; able to thrive in an environment that would otherwise prove fatal to most other plants. Thus, despite the arid conditions, Welwitschia can survive for hundreds of years.
Welwitschia’s Survival Strategies Make It a Masterclass in Adaptation
The extraordinary survival of Welwitschia mirabilis is a result of a suite of ingenious adaptations. The most remarkable is its ability to extract moisture from the fog. Specialized tissues on its leaves, paired with the plant's low-growing habit, allow it to efficiently capture water droplets directly from the fog. In this case, the plant's leaves are equipped with stomata that remain open during foggy conditions, allowing it to absorb the moisture right from the air. The leaves' thick, leathery texture minimizes water loss through transpiration, further enhancing its water-use efficiency. Its deep taproot, also, allows it to access groundwater, providing an additional source of moisture during drier periods. All these adaptations are crucial for its survival.
Furthermore, Welwitschia mirabilis exhibits remarkable physiological adaptations to cope with water stress. It possesses a high tolerance to salinity and can withstand extreme temperature fluctuations. The plant's unique photosynthetic pathway, known as CAM (crassulacean acid metabolism), allows it to open its stomata (pores) at night to take in carbon dioxide and close them during the day to minimize water loss. Plus, the thick, fleshy leaves not only store water but also help regulate the soil temperature beneath them, keeping it cool and moist. This is particularly important in an environment where soil temperatures can become extreme.
The plants’ slow growth rate and ability to withstand environmental stressors is, also, another strategy, hence why one of the most amazing aspects of Welwitschia mirabilis is its exceptional longevity. Its slow growth rate allows it to conserve resources and survive long periods of drought. And, in this case, while precise age determination remains challenging, some specimens are estimated to be over 1,000 years old, with some potentially exceeding 2,000 years. Carbon dating suggests that most Welwitschias are, on average, 500 to 600 years old, and their estimated lifespan is between 400 and 1,500 years. This remarkable longevity is enabled by its unique growth habits and adaptations to the harsh desert environment. It, therefore, is one of those plants that could be deemed a true living fossil that has seen eras of environmental change.
Welwitschia Mirabilis' Cultural and Ecological Significance
Welwitschia plays a crucial role in the desert ecosystem, providing food and water for local people and even animals. The local Damara and Herero people, for instance, consume the seed cones raw or roasted. In fact, its Herero name is onyanga, which means 'onion' of the desert. Even more, this relic plant holds more cultural significance for the indigenous communities of Namibia in that it is revered as a symbol of resilience and longevity. Its leaves have, also, been used traditionally for different purposes, including thatching roofs and making medicinal remedies. Welwitschia is, therefore, an important part of the social heritage of the region, and country, even featuring on Namibia's coat of arms symbolizing the country's fortitude and tenacity.
Further to these, Welwitschia, also, plays a significant role in the fragile ecosystem of the Namib Desert. Its leaves provide shelter and habitat for various insects and small animals, contributing to the general biodiversity of the region. Desert-dwelling animals like zebras, oryx, and black rhinoceros, also, feed on the leaves of Welwitschia for a vital source of water. Plus, its deep roots help stabilize the sand dunes and prevent erosion. In addition to its ecological role, Welwitschia has been a subject of interest for botanists and naturalists who study its unique biology and evolutionary history. Its remarkable adaptations provide valuable insights into the mechanisms of plant survival in extreme environments and offer potential applications in biotechnology and agriculture. Research on this plant, could, for instance, contribute to further understanding of drought tolerance, salt tolerance, and other aspects of plant physiology. Its unique appearance and survival strategies, also, offer insights into ancient plant life.
However, its restricted distribution and sensitivity to habitat disturbance make it susceptible to human activities. Overgrazing by wildlife and livestock, habitat destruction, and illegal collection of plants pose significant threats to its survival. Conservation efforts are, therefore, crucial to protect this unique and, virtually, irreplaceable species and its habitat.
Growing Welwitschia Mirabilis
While Welwitschia is not a true succulent, it has attracted quite significant interest among succulent enthusiasts due to its caudiciform nature. Cultivating Welwitschia, therefore, requires simulating its native environment, using well-drained soil, and providing adequate moisture. The plant readily grows from seeds; which often display orthodox seed behavior. In general terms, this means that they may be stored for long periods at suitably low humidity and temperature. However, it is worth noting that its seeds collected from the wild are often heavily contaminated with spores of a fungus.
Welwitschia seeds naturally develop suitably low water concentrations as they ripen. Removal of the outer seed coverings enhances germination performance, which suggests that the seeds may display non-deep physiological dormancy. On planting the seed it is necessary to keep it moist but not immersed in water for the first two weeks of cultivation; it has been suggested that soaking the seeds in water before planting interferes with germination. The plant can be grown, either straight in the soil or in pots, and is relatively disease-free once established, although it is susceptible to fungal infections during its early stages.
Some Fascinating Facts About Welwitschia
- It is often referred to as a living fossil because it has remained relatively unchanged for millions of years, providing valuable insights into plant evolution.
- It has a unique pollination model in that, while it was once believed that a specific bug was responsible for pollinating it, it is now understood that various insects contribute to this process, emphasizing the plant's complex ecological relationships.
- Genomic studies and insights have revealed that Welwitschia has undergone significant evolutionary changes, including whole-genome duplications that have contributed to its unique adaptations and longevity.
- The largest plants are found in the south where the rainfall is the least. In the north where the rainfall is higher, the plants are much smaller, which could be attributed to those in the north competing with other savannah vegetation whereas those in the south have little or no competition.
Header image by @kasiafro. Unless otherwise indicated, photos are by welwitschia__mirabilis.
