User:Payxystaxna/Sandbox
- Original
| Welwitschia | |
|---|---|
| |
| Scientific classification | |
| Kingdom: | |
| Division: | |
| Class: | |
| Order: | Welwitschiales
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| Family: | Welwitschiaceae
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| Genus: | Welwitschia
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| Species: | W. mirabilis
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| Binomial name | |
| Welwitschia mirabilis | |
Welwitschia is a monotypic genus of gymnosperm plant, composed solely of the very distinct Welwitschia mirabilis. It is the only genus of the family Welwitschiaceae, in the order Welwitschiales, in the division Gnetophyta. The plant is considered a living fossil.[1]
The geographic distribution of Welwitschia mirabilis is limited to south-west Africa, specifically, to the Namib desert within the two countries, Namibia and Angola.
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Biology[edit]
Welwitschia grows from a short, thick trunk, with only two leaves that continuously grow from their base, and a long, thick taproot. After germination, the cotyledons grow to 25–35 mm in length, and are followed shortly afterwards by the appearance of two permanent leaves. These leaves are produced opposite of the cotyledons, and continue to grow throughout the entire life of the plant. They eventually grow to a length of 2–4 m and usually become split into several strap-shaped sections, thus sometimes disguising the origin from only two leaves. After these appear, two cotyledonary buds appear; in these, the growing tip dies, causing elongation of the buds. Growth continues sideways, which forms the obconical growth of the stem. The species is dioecious, with separate male and female plants. Fertilization, that is, the transfer of the pollen from the male to the female strobili, is carried out by insects that are attracted by "nectar" produced on both male and female strobili.[2]
The age of the plants is difficult to assess, but they are very long-lived, living 1000 years or more. Some individuals may be more than 2000 years old. [citation needed]
The plant absorbs water through peculiar structures on its leaves, harvesting moisture originating from dew that forms during the night. As a further adaptation to the arid conditions and hot daytime temperatures in its environment, and as the only gymnosperm species known to do so, W. mirabilis uses the crassulacean acid metabolism (CAM) pathway for carbon fixation in photosynthesis.[3]
Named after the Slovenian botanist Dr. Friedrich Welwitsch who discovered it in 1860, it is one of the oddest plants in existence. Although considered endangered due to its very slow growth and despite the fact that older plants are often sought by collectors, a fair number of plants exist in the wild. The plants living in Angola are better protected than the plants in Namibia, owing to the relatively high concentration of landmines in Angola, which keep collectors away [citation needed].
The species grows readily from seed, which may be purchased from specialty seed dealers. The seed must be kept moist for the first couple of weeks and exposed to as much heat and light as possible during this time. Seeds collected from the wild are often heavily contaminated with spores of Aspergillus niger, which causes them to rot shortly after they germinate. Seeds from the Kirstenbosch National Botanical Garden in Cape Town, South Africa, or other cultivated sources are much cleaner and less likely to rot. [citation needed]
Scientific classification according to different sources[edit]
| After Systema Naturae 2000 | After University of Connecticut 2006 [2] | After ITIS (Integrated Taxonomic Information System) 2005 [3] | After Encyclopedia Britannica Online 2007 [4] | |
| Domain | Eukaryota | - | - | - |
| Kingdom | Plantae Haeckel, 1866 |
Plantae | Plantae | - |
| Subkingdom | Viridaeplantae Cavalier-Smith, 1981 |
- | Tracheobionta | - |
| Division | Tracheophyta Sinnott, 1935 ex Cavalier-Smith, 1998 |
Gnetophyta | Gnetophyta | Gnetophyta |
| Subdivision | Spermatophytina (auct.) Cavalier-Smith, 1998 | - | - | - |
| Infradivision | Gymnospermae auct. | - | - | - |
| Class | Gnetopsida | Welwitschiopsida | Gnetopsida | - |
| Order | Gnetales T.M. Fries, 1891 | Welwitschiales | Welwitschiales | Welwitschiales |
| Family | Welwitschiaceae Markgraf in Engler & Prantl, 1926 | Welwitschiaceae | Welwitschiaceae Markgr. | Welwitschiaceae |
| Genus | Welwitschia J.D. Hooker, 1862 | Welwitschia | Welwitschia J. D. Hooker, 1863 | Welwitschia |
| Species | Welwitschia mirabilis J.D. Hooker | Welwitschia mirabilis Hook. f. | Welwitschia mirabilis Hook. f. | Welwitschia mirabilis |
| In green | In green | In green | Identical names with different authors |
| In red | - | - | Different names with different authors |
Heraldry[edit]
The plant figures as a charge in the national coat of arms of Namibia, as well as that of Westelike Rugby Subunie.
See also[edit]
References[edit]
- ^ A. Lewington & E. Parker (1999). Ancient Trees: Trees that Live for a Thousand Years. Collins & Brown Ltd. ISBN 1-85585-704-9.
- ^ Wetschnig W, Depisch B (1999). "Pollination biology of Welwitschia mirabilis HOOK. f. (Welwitschiaceae, Gnetopsida)". Phyton-Annales Rei Botanicae. 39: 167.
- ^ von Willert DJ, Armbruster N, Drees T, Zaborowski M (2005). "Welwitschia mirabilis: CAM or not CAM - what is the answer?". Functional Plant Biology. 32: 389. doi:10.1071/FP01241.
{{cite journal}}: CS1 maint: multiple names: authors list (link)
External links[edit]
Category:Gnetophyta Category:Endangered species Category:Flora of Angola Category:Living fossils Category:Flora of Southern Africa
- Template
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For species, the taxobox template might be: Taxobox template
Description[edit]
Ideally would include:
- plant morphology factors such as height, size and structure of flower or fruiting body, nature of inflorescence, etc.
- plant anatomy such as nature of vascular bundles and other tissues. Describe cell walls and other structures.
- biochemistry: describe pigments (e.g. anthocyanins), defenses against herbivory, psychoactive or culinary compounds, and anything else which distinguishes it from other plants (this can also be covered in sections such as Medicine and Ecology).
- evolutionary development: If known, what genes regulate flower development, growth, water management, and any other processes, and how this relates to phylogeny.
For features which are also true of a large number of related plants (for example, traits which are true of the family for a genus or species article) summarize the most interesting, but link to other articles for details. If there is nothing to say specific to the subject of the article, do not make a large number of generic statements (for example, things true of plants in general) just to cover all the topics.
Taxonomy[edit]
Distribution[edit]
Ecology[edit]
Describe myco-heterotrophy or parasitism if present. Describe the native habitat(s) (what kind of soil? what other plants live there? do we have an article such as pine barren or mangrove swamp to link to?). Discuss pollinators and herbivores.
Cultivation[edit]
This section typically would list the general purpose/location of cultivation (farms, gardens, landscaping, etc), and something about different cultivated varieties. Say what part of the plant it is grown for (roots, flowers, leaves, etc). Give a general idea of the growing conditions (mediterranean climate, hot weather, cold weather, long season, etc), but not so much as to make the article a WP:NOT#HOWTO.
For food plants or other crops grown on a large scale, potential content includes:
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- environmental/sustainability aspects
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One possible source of information is the FAO.
Cultivation history[edit]
Propagation[edit]
Pests and diseases[edit]
Harvest[edit]
Uses[edit]
Medicine[edit]
Food[edit]
Fiber[edit]
Fuel[edit]
Timber[edit]
History[edit]
References[edit]
Categories should be defined near the end of the article.
Please include a direct parent category in the taxonomy whenever possible; for a species, the family is likely an available category. For a family, the order is probably available.
There are some additional subcategories that may be helpful, such as Category:Herbs, Category:Legumes, Category:Edible plants, and so on. See the subcategories under Category:Plants); most of the subcategories listed there have lower-level subcategories that may fit better. Multiple categories may be relevant.