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A weird African plant

10/29/02 12:00AM By Ruth Page
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(Host) There are a number of plants that can survive on earth for many hundreds of years. Today, commentator Ruth Page describes one that hangs onto its first two leaves for all that time, and rarely produces any more.

(Page) Quite a few people will travel the earth to observe unusual animals like the giant worm of Australia or beauties such as the golden tamarin of South America. But folks who circle the globe to see unique and peculiar plants are fewer, and usually scientists.

"[These plants] look like giant spiders creeping over the hills," reported botanist Judy Jernstedt, after traveling to southwestern Africa to see something called welwitschia, that from a distance looks like a pile of trash.

The adult plant has just two long, strap-like leaves that never fall off, even though they may have to hang there for up to 1,500 years. Desert winds beat them into ribbons, which become a tangled mess over the centuries, but they don't fall off. For the past 140 years, taxonomists haven't been able to agree on exactly where the strange plants fit on the tree of life.

First discovered by two plant explorers from Kew Gardens in England in 1860, welwitschia was called "the ugliest plant I've ever seen" by the curator. "But," he added, "welwitschia is out of the question the most wonderful plant ever brought to this country." Taxonomists at least agreed with that, because they dubbed the plants welwitschia mirabilis.

Science News says the plant's stem ends in a shallow bowl that can grow to the size of a hubcap. The two broad leaves grow from its rim to defy the desert winds. The plant produces cones rather than flowers, and each plant is either male or female. To attract pollinators, the plant exudes droplets of a sweet liquid. Discussion continues on whether welwitschia is a gymnosperm - such as a conifer - because of its cones; or an angiosperm, a flowering plant. Examination in the lab showed the plant cells match processes seen in flowering plants.

Some think it might be a missing link between the cone-bearing plants and the flowering plants, but no one is sure. Scientists continue to scratch their heads in wonder. The have discovered, though, how the enduring leaves can hang on, albeit in ribbons, for more than a 150 centuries. The leaves grow from their bases, like hair; when the tips break off, the growth continues. A few of the plants can sprout an additional leaf or two from their center, but it took researchers a long time to find any, even in an area where welwitschias flourish.

This is Ruth Page describing one or more of evolution's wonders well worth keeping.
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