Xanthorrhoea

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iXanthorrhoea

Scientific classification
Kingdom: Plantae
Division: Magnoliophyta
Class: Liliopsida
Order: Asparagales
Family: Xanthorrhoeaceae
Dumort.
Genus: Xanthorrhoea
Sol. ex Sm.
Species

see text

Xanthorrhoea is a genus of flowering plants native to Australia and a member of family Xanthorrhoeaceae. The Xanthorrhoeaceae are monocots, part of order Asparagales. There are 28 species of Xanthorrhoea, all are perennials and have a secondary thickening meristem in the stem. Many, but not all, species develop an above ground stem. This is rough-surfaced, built from accumulated leaf-bases around the secondarily thickened trunk. The trunk is sometimes unbranched, some species will branch if the growing point is damaged and others naturally grow numerous branches. Flowers are borne on a long spike above a bare section called a scape, the total length can be up to four metres long in some species. Flowering occurs in a distinct flowering period, which varies for each species. Flowering can be stimulated by bushfire, in which case it occurs in the next flowering period after the fire.

It is commonly believed that the Xanthorrhoea grow at a rate of about an inch (2½ cm) per century. Xanthorrhoea do grow very slowly, but this is a gross underestimate: after an initial establishment phase the average rate of growth varies for each species but can be as high as about 2½ cm per year. Thus a five-metre tall member of one of the fastest growing Xanthorrhoea would be about 200 years old.

Xanthorrhoea may be cultivated, as seed is easily collected and germinated. Whilst they do grow slowly, quite attractive plants with short trunks (10 cm) and leaf crowns up to 1.5 m can be achieved in 10 years. The slow growth rate means that it can take 30 years to achieve a specimen with a significant trunk. Most Xanthorrhoea sold in nurseries are established plants taken from bushland. Nurseries charge high prices for the plants. However, there is a very low survival rate for nursery purchased plants, which may take 3-4 years to die. The only examples of successful transplanting have been where a substantial amount of soil ( > 1 cubic metre) has been taken with the plants.

Flower spikes on "blackboy" trees
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Flower spikes on "blackboy" trees
The top of a Xanthorrhoea
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The top of a Xanthorrhoea
A large group of Xanthorrhoea
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A large group of Xanthorrhoea
A group of flowering Xanthorrhoea
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A group of flowering Xanthorrhoea
Early stages of a flowering Xanthorrhoea stem
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Early stages of a flowering Xanthorrhoea stem
Flowering Xanthorrhoea
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Flowering Xanthorrhoea
Old flower stem after seeds have been ejected
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Old flower stem after seeds have been ejected

The best known common name for the Xanthorrhoea is blackboy. This name refers to the purported similarity in appearance of the trunked species to an Aboriginal boy holding an upright spear. Some consider this name to be politically incorrect, preferring grasstree, or in the South West the Noongar name balga for X. preissei. In South Australia it is commonly known as yakka, also spelled yacca and yacka. This probably is from a South Australian Aboriginal language.[1], such as Kaurna.

Contents

[edit] Species

  • Xanthorrhoea acanthostachya
  • Xanthorrhoea acaulis
  • Xanthorrhoea arborea
  • Xanthorrhoea arenaria
  • Xanthorrhoea australis
  • Xanthorrhoea bracteata
  • Xanthorrhoea brevistyla
  • Xanthorrhoea brunonis
  • Xanthorrhoea caespitosa
  • Xanthorrhoea concava
  • Xanthorrhoea drummondii
  • Xanthorrhoea fulva
  • Xanthorrhoea glauca
  • Xanthorrhoea gracilis
  • Xanthorrhoea johnsonii
  • Xanthorrhoea latifolia
  • Xanthorrhoea macronema
  • Xanthorrhoea malacophylla
  • Xanthorrhoea media
  • Xanthorrhoea minor
  • Xanthorrhoea nana
  • Xanthorrhoea platyphylla
  • Xanthorrhoea preissii
  • Xanthorrhoea pumilio
  • Xanthorrhoea reflexa
  • Xanthorrhoea resinifera
  • Xanthorrhoea semiplana
  • Xanthorrhoea thorntonii

[edit] See also

  • Kingia, an unrelated Australian grasstree that is often thought to be a Xanthorrhoea. Kingia is also often called blackboy.

[edit] References

  1. ^ Peters, Pam, The Cambridge Australian English Style Guide, Cambridge University Press, 1996, p823

[edit] External links

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