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{{Taxobox
Não vou reverter mais porque já vi que estás armado em parvo. Compara as duas versões e, de mente aberta, vê lá se não tenho razão.
| name = ''Welwitschia''
| image = Welwitchia.jpg
| image_width = 270px
| regnum = [[Plant]]ae
| divisio = [[Gnetophyta]]
| classis = [[Gnetophyta|Gnetopsida]]
| ordo = '''Welwitschiales'''
| familia = '''Welwitschiaceae'''
| genus = '''''Welwitschia'''''
| species = '''''W. mirabilis'''''
| binomial = ''Welwitschia mirabilis''
| binomial_authority = [[Joseph Dalton Hooker|Hook.f.]]
}}


'''''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]].<ref name="Lewington & Parker">{{cite book | author = A. Lewington & E. Parker | title = Ancient Trees: Trees that Live for a Thousand Years | year = 1999 | publisher = Collins & Brown Ltd. | id = ISBN 1-85585-704-9}}</ref>
'''A tua versão:'''
[[Image:Welwitschia-mirabilis-female.jpg|thumb|left|Female plant]] The geographic distribution of ''Welwitschia mirabilis'' is limited to south-west [[Africa]], specifically, to the [[Namib desert]] within the two countries, [[Namibia]] and [[Angola]].
[[Image:Welwitschia mirabilis(2).jpg|left|thumb|The largest known ''Welwitschia'', nicknamed "The Big ''Welwitschia''", stands 1.4 m tall and is over 4 m in diameter.]]


==Biology==
Rhynchocyon petersi é uma espécie de musaranho-elefante da família Macroscelididae. Pode ser encontrada na Tanzânia (incluindo as ilhas de Mafia e Zanzibar) e no sudoeste do Quênia.
[[Image:N-welwitschia-2.jpg|thumb|Detail photograph of female plant]]
[[Image:N-welwitschia-3.jpg|thumb|Detail photograph of male plant]]
Welwitschia grows from a short, thick trunk, with only two [[leaf|leaves]] that continuously grow from their base, and a long, thick [[taproot]]. After germination, the [[cotyledon]]s grow to 25&ndash;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&ndash;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 [[plant sexuality|dioecious]], with separate male and female plants. [[Pollination|Fertilization]], that is, the transfer of the pollen from the male to the female flowers, is apparently carried out by insects that are attracted by "nectar" produced on both male and female flowers.<ref name="Wetschnig and Depisch">{{cite journal|author=Wetschnig W, Depisch B|year= 1999|title=Pollination biology of ''Welwitschia mirabilis'' HOOK. f. (Welwitschiaceae, Gnetopsida)|journal=Phyton-Annales Rei Botanicae|volume=39|pages=167}}</ref>


The age of the plants is difficult to assess, but it is believed that they are very long-lived, possibly living 1000 years or more. Some individuals may be more than 2000 years old.
Referências
* SCHLITTER, D. A. Order Macroscelidae. In: WILSON, D. E.; REEDER, D. M. (Eds.). Mammal Species of the World: A Taxonomic and Geographic Reference. 3. ed. Baltimore: John Hopkins University Press, 2005. v. 1, p. 82-85.
* IUCN 2008. Rhynchocyon petersi
*'''Igual-->''' 2008 IUCN Red List of Threatened Species. <www.iucnredlist.org>. Acessado em 7 de outubro de 2008.


The plant is thought to absorb 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.<ref name="von Willert et al">{{cite journal|author=von Willert DJ, Armbruster N, Drees T, Zaborowski M |year= 2005|title=''Welwitschia mirabilis'': CAM or not CAM - what is the answer?|journal=Functional Plant Biology|volume=32|pages=389|doi=10.1071/FP01241}}</ref> Named after the [[Slovenia]]n [[botanist]] Dr. [[Friedrich Welwitsch]] who discovered it in 1860, it is generally considered to be 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 generally considered to be better protected than the plants in [[Namibia]], owing to the relatively high concentration of [[land mine|landmines]] in Angola, which keep collectors away {{Fact|date=February 2007}}.
'''A minha versão:'''


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. {{Fact|date=May 2007}}
Rhynchocyon petersi é uma espécie de mamífero da família Macroscelididae (musaranho-elefante). Pode ser encontrada na Tanzânia (incluindo as ilhas de Mafia e Zanzibar) e no sudoeste do Quênia.


==Scientific classification according to different sources==
Referências
* SCHLITTER, D. A. Order Macroscelidae. In: WILSON, D. E.; REEDER, D. M. (Eds.). Mammal Species of the World: A Taxonomic and Geographic Reference. 3. ed. Baltimore: John Hopkins University Press, 2005. v. 1, p. 82-85.
* FitzGibbon, C. & Rathbun, G. 2006.
*'''Igual-->''' Rhynchocyon petersi. 2008 IUCN Red List of Threatened Species. <www.iucnredlist.org>. Acessado em 7 de outubro de 2008.


{| border="1" cellspacing="0" cellpadding="1"
E refiro que dizeres que o '''Rhynchocyon petersi é uma espécie de musaranho-elefante''' é uma burrada de todo o tamanho, o '''Rhynchocyon petersi é uma espécie de mamífero''', não existe nenhuma espécie ''musaranho-elefante'' isto é um absurdo, as espécies são: Mamíferos, Aves, Repteis, Peixes, Batráquios, Insectos, etc, etc. Por isso disse, não alteres aquilo que não sabes. O ter colocado à frente de '''Macroscelididae (musaranho-elefante)''', foi uma situação de consenso, porque nem sequer lá devia estar. [[User:Oskulo|Oskulo]] ([[User talk:Oskulo|talk]]) 14:11, 8 October 2008 (UTC) tenho dito.
|- align="center" bgcolor="#ffff99"
| &nbsp;
|After [[Systema Naturae 2000]]
[http://taxonomicon.taxonomy.nl/TaxonTree.aspx?id=4507&tree=0.1&syn=1]
|After [[University of Connecticut]] [[2006]] [http://florawww.eeb.uconn.edu/acc_num/199700061.html]
|After [[ITIS]] (Integrated Taxonomic Information System) 2005 [http://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=18060]</small>
|After [[Encyclopedia Britannica Online]] 2007 [http://www.britannica.com/eb/article-34754/gnetophyte]
|- align="center" bgcolor="#ffff99"
|[[Domain (biology)|Domain]]
| bgcolor="#afdead" |[[Eucariote|Eukaryota]]
|<small>-</small>
|<small>-</small>
|<small>-</small>
|- align="center" bgcolor="#ffff99"
|[[Kingdom (biology)|Kingdom]]
| bgcolor="#afdead" |[[Plantae]]<br/>[[Ernst Haeckel|Haeckel]], [[1866]]
| bgcolor="#afdead" | [[Plantae]]
|bgcolor="#afdead" |[[Plantae]]</small>
|<small>-</small>
|- align="center" bgcolor="#ffff99"
|[[Subkingdom]]
| bgcolor="ff9999" |[[Viridaeplantae]] [[Cavalier-Smith]],<br/> [[1981]]
|<small>-</small>
|bgcolor="ff9999" |[[Tracheobionta]]
|<small>-</small>
|- align="center" bgcolor="#ffff99"
|[[Division (botany)|Division]]
| bgcolor="ff9999" |[[Tracheophyta]] [[Edmund Ware Sinnott|Sinnott]], [[1935]] ex [[Cavalier-Smith]], <br/>[[1998]]
| bgcolor="#C7CF00" | [[Gnetophyta]]
| bgcolor="#C7CF00" |[[Gnetophyta]]</small>
| bgcolor="#C7CF00" |[[Gnetophyta]]
|- align="center" bgcolor="#ffff99"
|[[Subdivision (botany)|Subdivision]]
| bgcolor="ff9999" |[[Spermatophytina]] (auct.) [[Cavalier-Smith]], [[1998]]
|<small>-</small>
|<small>-</small>
|<small>-</small>
|- align="center" bgcolor="#ffff99"
|[[Infradivision]]
| bgcolor="ff9999" |[[Gymnospermae]] auct.
| -
|<small>-</small>
| -
|- align="center" bgcolor="#ffff99"
|[[Class (biology)|Class]]
| style="border: 1px solid black; background:#90EE90;" |[[Gnetopsida]]
| bgcolor="ff9999" | [[Welwitschiopsida]]
| style="border: 1px solid black; background:#90EE90;" |Gnetopsida </small>
|<small>-</small>
|- align="center" bgcolor="#ffff99"
|[[Order (biology)|Order]]</small>
| bgcolor="ff9999" |[[Gnetales]] [[T.M. Fries]], [[1891]]
| bgcolor="#afdead" | [[Welwitschiales]]
| bgcolor="#afdead" |[[Welwitschiales]]
| bgcolor="#afdead" |[[Welwitschiales]]
|- align="center" bgcolor="#ffff99"
|[[Family (biology)|Family]]
| bgcolor="#afdead" |[[Welwitschiaceae]] Markgraf in [[Adolf Engler|Engler]] & [[Karl Anton Eugen Prantl|Prantl]], [[1926]]
| bgcolor="#afdead" | [[Welwitschiaceae]]
| bgcolor="#afdead" |[[Welwitschiaceae]] Markgr.
| bgcolor="#afdead" |[[Welwitschiaceae]]
|- align="center" bgcolor="#ffff99"
|[[Genus]]
| bgcolor="#afdead" | ''[[Welwitschia]]'' [[Joseph Dalton Hooker|J.D. Hooker]], [[1862]]
| bgcolor="#afdead" | ''[[Welwitschia]]''
| bgcolor="#afdead" | ''[[Welwitschia]]'' [[Joseph Dalton Hooker| J. D. Hooker]], [[1863]]
| bgcolor="#afdead" | ''[[Welwitschia]]''
|- align="center" bgcolor="#ffff99"
|[[Species]]
| bgcolor="#afdead" | ''Welwitschia mirabilis'' [[Joseph Dalton Hooker|J.D. Hooker]]
| bgcolor="#afdead" | ''Welwitschia mirabilis'' [[Joseph Dalton Hooker|Hook. f.]]
| bgcolor="#afdead" | ''Welwitschia mirabilis'' [[Joseph Dalton Hooker|Hook. f.]]
| bgcolor="#afdead" | ''Welwitschia mirabilis''
|}

{| border="1" cellspacing="0" cellpadding="1"
|- align="center"
| bgcolor="#afdead" | In green
| style="background:#90EE90;" | In green
| bgcolor="#C7CF00" | In green
|<small>Identical names with different authors</small>
|- align="center"
| bgcolor="ff9999" | In red
| -
| -
|<small>Different names with different authors</small>
|}

==Heraldry==
The plant figures as a [[charge (heraldry)|charge]] in the national [[coat of arms of Namibia]], as well as that of Westelike Rugby Subunie.

==See also==
*[[List of Southern African indigenous trees]]

==References==
<references />

==External links==
{{Commons|Welwitschia mirabilis|Welwitschia}}
*[http://www.conifers.org/we/index.htm Gymnosperm database: ''Welwitschia'']
*[http://florawww.eeb.uconn.edu/acc_num/199700061.html Ecology & Evolutionary Biology Conservatory]

[[Category:Gnetophyta]]
[[Category:Endangered species]]
[[Category:Flora of Africa]]
[[Category:Flora of Angola]]
[[Category:Living fossils]]

{{Link FA|de}}

[[af:Welwitschia]]
[[cs:Welwitschie podivná]]
[[da:Welwitschia-ordenen]]
[[de:Welwitschie]]
[[et:Velvitšia]]
[[es:Welwitschia mirabilis]]
[[fr:Welwitschia mirabilis]]
[[it:Welwitschia mirabilis]]
[[he:ולויטשיה]]
[[ka:ველვიჩია]]
[[ml:വെല്‍വിറ്റ്ഷിയ മിരാബിലിസ്]]
[[nl:Welwitschia]]
[[ja:ウェルウィッチア]]
[[no:Welwitschia mirabilis]]
[[pl:Welwiczja przedziwna]]
[[pt:Welwitschia]]
[[ro:Welwitschia mirabilis]]
[[ru:Вельвичия]]
[[simple:Welwitschia]]
[[fi:Welwitschia]]
[[sv:Welwitschia]]
[[zh:百歲蘭]]

Revision as of 14:12, 8 October 2008

Welwitschia
Scientific classification
Kingdom:
Plantae
Division:
Gnetophyta
Class:
Gnetopsida
Order:
Welwitschiales
Family:
Welwitschiaceae
Genus:
Welwitschia
Species:
W. mirabilis
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]

Female plant

The geographic distribution of Welwitschia mirabilis is limited to south-west Africa, specifically, to the Namib desert within the two countries, Namibia and Angola.

The largest known Welwitschia, nicknamed "The Big Welwitschia", stands 1.4 m tall and is over 4 m in diameter.

Biology

Detail photograph of female plant
Detail photograph of male plant

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 flowers, is apparently carried out by insects that are attracted by "nectar" produced on both male and female flowers.[2]

The age of the plants is difficult to assess, but it is believed that they are very long-lived, possibly living 1000 years or more. Some individuals may be more than 2000 years old.

The plant is thought to absorb 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 generally considered to be 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 generally considered to be 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

  After Systema Naturae 2000

[1]

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

The plant figures as a charge in the national coat of arms of Namibia, as well as that of Westelike Rugby Subunie.

See also

References

  1. ^ A. Lewington & E. Parker (1999). Ancient Trees: Trees that Live for a Thousand Years. Collins & Brown Ltd. ISBN 1-85585-704-9.
  2. ^ Wetschnig W, Depisch B (1999). "Pollination biology of Welwitschia mirabilis HOOK. f. (Welwitschiaceae, Gnetopsida)". Phyton-Annales Rei Botanicae. 39: 167.
  3. ^ 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)
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