Welwitschia ( Welwitschia mirabilis) -
Welwitschia - Welwitschia mirabilis
Welwitschia is a monotypic genus of gymnosperm plant, composed solely of the very distinct Welwitschia mirabilis. It is the only genus of the family Welwitschiaceae and order Welwitschiales, in the division Gnetophyta. The plant, which is considered a living fossil, is named after the Austrian botanist Friedrich Welwitsch who discovered it in 1859. The geographic distribution of Welwitschia mirabilis is limited to the Namib desert within Namibia and Angola.
It’s hideous, looking like something that died out to sea and washed up on the beach. It’s bizarre. It’s also extremely rare and incredibly unique. The
Welwitschia mirabilis is a flower – that’s right, a flower – found only in the Namib desert within Namibia and Angola.
Çowever, they are not widely found in Namibia due to locals who dig them up and collect them. The minefields in Angola keep them plenty safe.
Welwitschia és the latter country’s national flower. The plants are seldom found far from the coast, and the distribution coincides with fog. Although the plant is not endangered, it is protected by law.
Considered a living fossil, Welwitschia is thought to be a holdover from the Jurassic period, when such plants – called gymnosperms – dominated the landscape. Over millennia, similar plants disappeared, but welwitschia managed to survive despite drastic changes to the climate of its environment.
Welwitschia mirabilis was discovered by the Austrian botanist, explorer and medical doctor, Friedrich Welwitsch, in 1859 in the Namib Desert of southern Angola. The story goes that he was so overcome by his find that he knelt down next to it and simply stared! Thomas Baines, the renowned artist and traveler, also found a plant in the dry bed of the Swakop River in Namibia in 1861. Welwitsch sent the first material of Welwitschia to Sir Joseph Dalton Hooker, Director of Kew, in 1862. Hooker described it and named it in honour of Welwitsch, despite the fact that Welwitsch recommended that it be named Tumboa, its native Angolan name. Its species name mirabilis means marvellous or wonderful in Latin. The specific name was later changed to bainesii to honour both men involved in its discovery, although mirabilis is the name recognized today.
This plant may look like a messy pile of leaves, but it actually only has two, which continue growing throughout the life of the plant, reaching lengths of up to
Welwitschia grows from a short, thick, woody trunk, with only two leaves that continuously grow from their base, and a long, thick taproot. After germination, the cotyledons grow to 25–35 mm in length, and are followed shortly afterward by the appearance of two permanent leaves. These leaves are produced opposite of the cotyledons, and continue to grow throughout the entire life of the plant. They eventually grow to a length of 2–4 m and usually become split, frayed and shredded into several strap-shaped sections by wind and sand, to resemble a larger quantity of leaves.
The growing tips of the two cotyledonary buds die, causing elongation of the buds. Growth continues sideways, which forms the obconical growth of the stem. The species is dioecious, with separate male and female plants. Fertilization, that is, the transfer of the pollen from the male to the female strobili, is carried out by insects — mostly flies and infrequently wasps and bees — that are attracted by "nectar" produced on both male and female strobili.
The age of the plants is difficult to assess, but they are very long-lived, living 1000 years or more. Some individuals may be more than 2000 years old. The biggest Welwitschia plant is 4.6 feet tall and 13 feet wide.
When it comes to most living things, water and food are a necessity. However, for the Welwitschia mirabilis,
75 mm of water during an entire year work just fine. 25 mm of this usually comes from rain while the other
50 mm are provided by the ocean fog. However, the lack for water may explain this plant’s appearance- it’s dry, rugged, flimsy look most definitely fits the mold.
Welwitschia is ecologically highly specialized, and is adapted to grow under arid conditions receiving regular fog. This regular, dense fog is formed when the cold north-flowing Benguela Current meets the hot air coming off the Namib Desert. The fog develops during the night and usually subsides by about 10 a.m. The leaves are broad and large and droop downwards. This is an ideal way for it to water its own roots from water collected by condensation. It also has numerous stomata on both leaf surfaces and fog-water is taken up directly through these stomata. The fog has been estimated to contribute 50 mm in annual rainfall, but in spite of the fog, the plants are still dependent on additional sources. Rainfall in this area is erratic and extremely low, only 10 - 100 mm during the summer months. In some years, no rain falls at all. The plants are often confined to dry watercourses or next to higher rainfall regions, and they occasionally grow on rocky outcrops. All these habitats point to an additional underground water supply. The plant has a long taproot, allowing it to reach this underground water.
There are other interesting environmental adaptations. The largest plants are found to the south where the rainfall is the least, whereas in the north where the rainfall is higher the plants are much smaller. The most likely reason for this is that the plants in the north have to compete with savannah vegetation whereas those in the south have little or no competition. Another interesting adaptation is the corky bark, which could be the result of thousands of years of exposure to grass fires so commonly associated with savannah.
Antelope and rhino chew the leaves for their juice during times of drought, and spit out the tough fibres. They also eat the soft part near the groove. This luckily does not damage the plant as they simply grow out again from the meristematic tissue.
The core, especially of the female plant, was used as food for people in earlier times. It is said to be very tasty either raw or baked in hot ashes, and this is how it got its Herero name, onyanga, which means onion of the desert.