Friday, August 29, 2008

Life Photo Meme: Wild Welwitschia

Kingdom: Plantae

'Phylum: Gymnospermae' (not technically a phylum, but a useful taxonomic grouping)

Class: Gnetopsida

Order: Welwitschiales

Family: Welwitschiaceae

This is an absolutely wild plant, that I would not mind seeing in the wild. This is Welwitschia mirabilis, a plant native to the 'fog belt' of the Namib desert in Africa. It is a gymnosperm, a group of plants which bear cones instead of flowers for reproduction (like cycads and pine trees), and is the only gymnosperm to have adapted to desert life. However, the male cones (male and female cones are located on different plants) have structures which resemble those found in a flower.

They are also super unusual in the way they grow. Most plants have an apical meristem which allows them to grow upwards. In Welwitschia, the apical meristem dies shortly after germination, leaving them only able to grow outward, and upwards a bit at the edges of the trunk. Think of a tree trunk that's been lopped off close to the ground, and hollowed out in the center like a bowl, and you have the basic shape of a Welwitschia trunk.

Finally, their leaves are the most unique in the plant kingdom. They are the only plant to posses permanent leaves. Most plants grow leaves from outgrowths of the apical meristem, these dividing cells bud off to form leaves at the tips of branches, or at certain nodes along the branch. Welwitschia possesses only two leaves which grow from the sides of the trunk shortly after germination. These two strap-shaped leaves continue to grow for the rest of the plants life, from the base of the leaf. The leaves also posses many grooves and blind ends, as well as stomata along the top of the leaf, which allows the plant to collect water from the morning fog.

Welwitschias live for 500-600 years.

1 comment:

Eric Heupel said...

Now that IS a wild plant!