A trip into ancient times

While in Swakopmund, do take a trip to the Giant Welwitschia, a plant of ancient origin, which is remarkable for several reasons. Firstly it is regarded as a link between the very ancient gymnosperms and the much younger angiosperms. Gymnosperms have needles, their seeds deve-lop inside cones and they are generally pollinated by the wind while angiosperms have leaves, their seeds grow inside an ovary, usually surrounded by colourful petals, and many of them are pollinated by insects. The Welwitschia, however, has parallel-veined leaves like the higher develop angiosperms [grasses or palms] but its seeds grow inside cones. It is the only example of a cone-bearing plant in Namibia. Since it is assumed that angiosperms only came into existence about 120 - 130 million years ago, the origin of Welwitschia may reach very far back into the history of the earth. The plant is a national symbol and can be found in the Namibian coat of arms.
The Welwitschia has adapted to its harsh environment in remarkable ways. To mi-nimise evaporation and heat exposure its trunk reaches into the ground for 1.5 - 3 m while its roots may reach a depth of 30 metres. The unbranched top of the dwarf tree may rise above the ground for 1.8 m at most. Initially the top of the trunk is level with the ground. The two cotyledons, which in angiosperms die off once true leaves have developed, in this case continue to grow throughout the lifetime of the Welwitschia, which may be up to 2000 years. They appear to be a number of tangled leaves because they are shredded by the strong winds typical of their habitat.
Over time the top of the woody trunk splits into two convoluted sections covered with a corky layer protecting it from heat and evaporation. The subsequent growth of the plant only occurs around the edge of this central depression. Below the soil the trunk branches into numerous thin lateral roots which draw moisture form the deeper regions of the ground, however, it also sends out a web of very fine roots throughout the top layer of the soil in a radius of about 1.5 m around the plant. These roots are vital for the plant as they absorb moisture derived from the frequent heavy fogs blowing in from the cold Atlantic Ocean. It is due to these roots that a Welwitschia cannot be transplanted since they would be destroyed in the process. The fence around the largest of the Welwitschias at the "Giant Welwitschia" and the rings of stone around some of the other plants in the vicinity serve to protect these roots, which would be damaged by people walking or driving too close to the plant, disturbing and compressing the sand in the process
The Welwitschia occurs in the central Namib north of the Kuiseb river into southern Angola, where extensive fields of these plants exist. The largest Welwitschias in Namibia grow in the Messum Crater. There are many smaller Welwitschias in the Mopane savannah west of Khorixas near the petrified forest. Welwitschias usually grow in dry watercourses and depressions where water collects after downpours. They are not succulents and will die if their roots dry out completely.
Male and female flowers grow on diffe-rent plants. The cone-shaped salmon co-loured male flowers are more slender than the blue green female cones. Large amounts of pollen are produced by the male cones and the female cones are covered in a sticky substance to capture the pollen. Nevertheless, scientists have not yet come to a final conclusion regarding the manner in which these plants are pollinated since they have also found bees collecting Welwitschia pollen. In fact, hardly any young Welwitschias can be found in nature. In order to germinate, the seeds need moisture over a continuous period of several days, a very rare occurrence in the desert. Therefore, most of the Welwitschias found at a certain locality usually are of the same age as they all germinated during the same advantageous period. Also, a large percentage of the numerous seeds produced are infested and destroyed by a certain fungus. In times of drought the leaves are sometimes chewed by animals in search of moisture, but the resultant fibres are spat out.
Names: Tumboa, from the Angolan name "n'Tumbo", meaning 'blunt'. The Otjiherero name "onyanga yokuware" means 'the onion growing close to the coast'. The Austrian botanist and physician Friedrich Welwitsch discovered the plant along the southern coast of Angola in 1869 and it was subsequently named after him. The species name mirabilis meaning 'amazing, wonderful' refers to the many unusual features of the plant explained above.
Even older plants can be found along the road to the Giant Welwitschia after the turn-off towards the so-called moon landscape, where it passes through an extensive lichen field. Lichens are best visible on a wet and overcast morning when they unfold to absorb the moisture which also intensifies their colours. However, you will have to get out of your vehicle and onto your knees to discover the bright orange or black crusts on white stones or to recognise the lumpy surface of the sand for sand grains stuck together by slightly greenish lichens. Lichens represent a symbiotic relationship of fungi and algae and are thought to have originated about 400 million years ago. The fungi catch water from fog, rain or even from unsaturated air, support the plant and attach it to the soil, while the algae photosynthesise and so provide food and energy, as well as colour [green, orange, grey and brown to black] to the lichen. Lichens come in three different shapes: crustose attached flat to rocks and soil, foliose resembling very fine tufts of grass, and wind blown. The latter are not attached to the soil, resemble rolled up bits of brown or black bark and collect in depressions. When moistened they unfold, taking on the appearance of flat bits of seaweed. Lichens grow several thousands of years old. They survive under circumstances intolerable to other plants - unpredictable climate, low temperatures, low light intensity, aridity, poor soil. They are the first plants to cover bare patches of soil, thus preventing erosion by water and wind and forming a microclimate beneficial to higher life forms. They also serve as food for animals such as springbok. Acids from lichens are used for colorants, perfumes and antibiotics. They are the first organisms to die during unbalanced ecological conditions. Being extremely slow growing - about 1 mm [yes, millimetre] per annum, they take decades to recover as is obvious from vehicle tracks in the Namib remaining visible 'for ever'. That is why one should avoid all off-road driving in the Namib and use only well-worn old tracks.
At a certain point the road passes through some hills marked by a ridges of black boulders called dolerite. The break-up of Gondwanaland 180 to 130 million years ago into South Ame-rica, Africa, India, Australia and Antarctica was accompanied by intense volcanic activity during which lava intruded into cracks in the earth's crust without, however, reaching the surface of the earth. In the course of time the lava cooled and hardened. Due to their volcanic origin these rocks are much harder and more resistant to erosion than the layers into which they were forced. As the softer surrounding rock is worn away, the black dolerite ridges remain, winding over the hills for several kilometres on some occasions even strewn over entire hills.
The giant Welwitschia can be found 50 km east of Swakopmund and with several stops along the road would take four to five hours. To find out more about the uniquely adapted ve-getation along this road take along "Namib Flora" by Pat Craven and illustrated by Christine Marais.