In June 2009 the Daily Telegraph in the UK ran a competition in their gardening section to find the “World’s Ugliest Plant”. The competition was won by the Corpse flower (Amorphophallus titanum) (no surprise there!) and coming in in fourth position with 12% of the votes was the Tree Tumbo (Welwitschia mirabilis). For me there were two surprises in that result. Firstly, in Namibia I have never heard the Welwitschia referred to as a Tree Tumbo, although this is apparently quite common in Angola, and secondly, I really hadn’t thought of it as an “ugly” plant. Bizarre, perhaps. Weird, perhaps. Certainly fascinating. But not really ugly.
So, just what is a Welwitschia mirabilis? Well, the Welwitschia was discovered by the Austrian botanist Friedrich Welwitsch, in 1859 in the Namib Desert of southern Angola. Thomas Baines, the well known artist and traveller, seems to have been the first European to take note of the plants in what is now Namibia, finding his first example of the plant in the dry bed of the Swakop River in1861. Welwitsch sent the first material of Welwitschia to Kew Gardens in 1862, and it was eventually named in his honour. The species name mirabilis means extraordinary, marvellous or wonderful in Latin.
The Welwitschia is limited in distribution to a narrow strip of the Namib Desert, stretching about 1 000 km northwards from the Kuiseb River in central Namibia into southern Angola. They are seldom found more than 150 km from the coast, and their distribution coincides with the fog belt, on which they are heavily dependant for their survival.
This extraordinary plant produces only two leaves that continue to grow throughout the life of the plant, reaching a length of up to four metres. Over time these leaves become split along their lengths and as they lie around the plant in a seemingly disorganized jumble, the fact that there are only two leaves is often not obvious. Although the age of the plants is difficult to assess, they live a long time and some of the older examples are thought to be in the vicinity of 2,000 years old. The largest recorded plants are to be found in the Messum Crater and on the Welwitschia Plains in Namibia. Strangely, the largest plants are found in the drier southern part of the range, with the plants in the wetter north being significantly smaller.
Welwitschias are dioecious, which means that there are separate male and female plants, and fertilization takes place through the transfer of pollen from the male to the female by insects that are attracted to the plants. They are classified as gymnosperms, although they differ quite considerably from other gymnosperms and have been placed in their own family, and are perhaps the last survivors of the plants from the Jurassic period when gymnosperms were dominant amongst the world’s flora.
Welwitschias are highly adapted to grow under the arid conditions of the Namib Desert in those areas receiving regular fog. Fog is formed along the west coast of southern Africa when the cold Benguela Current, making its way northwards along the coast, meets the hot air coming off the desert. The fog builds up during the night and dissipates by mid-morning. During this time, the fog condenses on the broad leaves of the Welwitschia and trickles downwards; thus each plant waters its own root system. In addition, the leaves are able to absorb some of the water directly, courtesy of the stomata located on the leaves. Rainfall along the stretch of coast favoured by the Welwitschia is very low and somewhat erratic, with no rain at all falling some years, and “good” years receiving up to 100 mm. The plants are equipped with very long taproots, reaching down up to 30 metres, to take maximum advantage of what little water is available.
These fascinating plants are featured on the coat-of-arms of the Republic of Namibia.