Saturday, August 22, 2009

Welwitschia mirabilis.

It is really amazing what a diversity of plants nature has to offer. Here is a plant that came to my notice a long time ago, its unusual name is: Welwitschia mirabilis. This curious plant is an amazing survivor of the arid regions of southwestern Africa and the Namibia Desert; This is a living relic of a flora long disappeared.
AN AMAZING SURVIVOR.
HERE in the Namibia Desert of southwestern Africa, the air is clear and crisp. It is a cloudless day. As the sun rises, so does the temperature. This is a world of sand dunes and windswept gravel plains. We look around in awe. What is that heap of green leaves in the distance? Looking closer, we find that we have stumbled upon one of the strangest plants in the world-the Welwitschia mirabilis. The second word of that scientific name is Latin for "wonderful."

In the wild, welwitschias are found only in desert regions of Angola and Namibia. They are so different from any other plant that scientists classify them as a unique family and genus made up of only one species. "Of the approximately 375,000 species of plants known to man, no other plant has succeeded in creating so much botanical interest as has Welwitschia; nor has any other plant so defied man's habit of categorizing," writes Chris Bornman in his book Welwitschia-Paradox of a Parched Paradise.

Welwitschias may look like a mass of leaves surrounding a tree stump, but the plant actually has only two leaves. These become shredded into strips by the desert wind. An Afrikaans name for it, tweeblaarkanniedood, literally means "two-leaf-cannotdie." And how apt that name is! Here daytime temperatures sometimes reach 40 degrees Celsius, and the nights can be bitterly cold with no trees to break the fierce winds. While most plants depend entirely on their roots to absorb water from the soil, that is not true of the welwitschia. The Namib averages less than 25 millimeters of rain a year, and sometimes there is no rain for years! Under such conditions, the welwitschia continues to grow and its leaves remain green. Scientists have long wondered how this is possible. The answer seems to be that welwitschia leaves absorb the morning fog carried into the desert by regular coastal winds.

The welwitschia does not shed its leaves and grow new ones. The original pair continue growing for the entire life of the plant. On being unravelled; one leaf was found to be over 8.8 meters long! Imagine what would happen if the ends of a welwitschia leaf did not die and wear off! "In a life span of 1500 years," explains the scientific magazine Veld & Flora, "Welwitschia could produce a leaf as long as [225 meters]." But can the plant really live that long? "Welwitschia plants grow slowly and often live 1,000 to 2,000 years," confirms The World Book Multimedia

Encyclopedia.
The welwitschia is indeed a wonderful survivor. What accounts for the fact that this unique plant lives so long in such harsh desert conditions?
I Hope you found this story interesting. Have you ever heard about this plant before? - Werner

1 comment:

Char (PSI Tutor:Mentor) said...

wow! i have never heard of this plant before. this was so an interesting article. What is the average height of the leaves? Is that a seedling above in the picture?