Leucadendron argenteum

taxobox
name = "Leucadendron argenteum"


status = VU
status_system = iucn2.3
regnum = Plantae
unranked_divisio = Angiosperms
unranked_classis = Eudicots
ordo = Proteales
familia = Proteaceae
genus = "Leucadendron"
species = "L. argenteum"
binomial = "Leucadendron argenteum"
binomial_authority = (L.) R.Br.|

"Leucadendron argenteum" (Silver tree, Silver leaf tree, Witteboom, or Silwerboom) is an endangered species in the family Proteaceae, endemic to a small area of the Cape Peninsula, Stellenbosch, and Paarl in South Africa, notably the Lion's Head area and the Kirstenbosch National Botanical Garden.

It is a small evergreen tree growing up to 5-7 m tall, exceptionally to 16 m tall. The leaves are lanceolate, 8-15 cm long and 2 cm broad, with a distinct silvery tone produced by dense silky hairs. The flowers are produced in dense globose inflorescences 4-5 cm diameter; it is dioecious, with separate male and female plants. The fruit is a woody cone-like structure, containing numerous seeds; the seeds have a silky-haired helicopter-like parachute, enabling them to disperse by wind.

An estimated 40 to 50 percent of the entire world's native population of these trees was destroyed between 26 January and 27 January in the 2006 Table Mountain fire [http://www.news24.com/News24/South_Africa/News/0,,2-7-1442_1871014,00.html] . However, as recruitment of seedlings only occurs naturally after fire this is a necessary stage in the life-cycle of this Fynbos species. Recruitment after the fire has been good, and the population has recovered totally. It will however take another few years before this population produces seeds, during which time it would be vulnerable to extinction by further fires.

Conservation

A major deterrent to propagation of the silver leaf tree is its short life span. Most individuals don't live more than 20 years. But that is not a problem for conservation as fires rejuvenate populations on average every 15-20 years by killing the surviving adults and stimulating the canopy-stored seed banks (in the cones) to be released and the soil-stored seed banks to germinate. Juveniles take 5-7 years to flower and set seed, whereafter the populations are ready to burn again.

Heraldry

" [S] tylized twigs of the silver tree" ["sic"] appear in the arms of the South Peninsula Municipality of South Africa. [http://www.national.archsrch.gov.za/sm300cv/smws/sm30ddf0?20060828203950B6626546&DN=00000010]

References

* Listed as Vulnerable (VU D2 v2.3)

External links

* [http://www.plantzafrica.com/plantklm/leucadadendronargent.htm "Leucadendron argenteum" Plantzafrica.com]
* [http://www.up.ac.za/academic/botany/garden/species/6.html "Leucadendron argenteum" at the University of Pretoria website]
* [http://protea.worldonline.co.za/cpldarge.htm "Leucadendron argenteum" in the Protea Atlas]