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8.5: Gnetophytes

  • Page ID
    63003
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    Gnetophytes (Phylum Gnetophyta)

    Gnetales are the least familiar group of gymnosperms. There are 112 species in the world (Christenhusz and Byng, 2016), being divided into three main subgroups: Welwitschia (1 species), Gnetales (43 species), and Ephedrales (68 species). Welwitschia is an odd-looking plant adapted to extremely arid environments, being native to the Namibian Desert in Africa (Angola and Namibia). It has a short stem and only develops two leaves over its long lifetime. Some of the oldest plants can be 3,000 years old. The leaves can reach up to 2 meters (6 feet) in length and will continue to grow the entire life of the plant. The leaves usually coil and get split by the wind (Figure \(\PageIndex{1}\)).

    Gymnosperm example by DutraElliott.jpg
    Figure \(\PageIndex{1}\): Welwitschia is an example of a gnetophyte. A) Close up of a female Welwitschia mirabilis, and B) Welwitschia mirabilis plant in its natural environment. By DutraElliott is licensed under CC BY-NC 4.0 via Flickr. A derivative of the original works of A) by Tris T7, CC BY 3.0, via Wikicommons. And B) wolfgang.mller54, CC BY 2.0, via Wikimedia Commons. Modifications: Photos were put together in a plate and labels added.

    An example of a plant in the Ephedrales group is Mormon tea (Ephedra spp.), which is common in arid regions of the Southwestern United States (Figure \(\PageIndex{2}\)). Mormon tea, and a similar species in China from which ephedrine is extracted, have been used for millennia for treating asthma. Currently, ephedrine is used to prevent low pressure during anesthesia and most of it is synthetically manufactured, although some Ephedra species are still cultivated for extraction of natural ephedrine.

    Figure \(\PageIndex{2}\): Mormon tea at Natural Bridges National Monument, Utah. By PaulaMejia is licensed under CC BY-NC-SA 2.0 via Flickr.

    This page titled 8.5: Gnetophytes is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by Daniela Dutra Elliott & Paula Mejia Velasquez.

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