Some species have a restricted range, others are widely distributed.Īccording to the World Checklist of Selected Plant Families, as of September 2014 the following species are accepted: List of Xanthorrhea species in Australia Diversity and distribution 5-metre-tall Xanthorrhea drummondii in the Avon Valley National Park, Western AustraliaĪ genus endemic to Australia, occurring in all national states and territories. However, later anatomical and phylogenetic research has supported the view of Dahlgren who regarded Xanthorrhoea as the sole member of his family Xanthorrhoeaceae sensu stricto, which is now treated as the subfamily Xanthorrhoeoideae. Some plant classification systems such as Cronquist have included a wide range of other genera in the same family as Xanthorrhoea. Both genera have at times been confused with xanthorrhoeas and misnamed as "grasstrees". Kingia and Dasypogon are unrelated Australian plants with a similar growth habit to Xanthorrhoea. The name grasstree is applied to many other plants. In South Australia, Xanthorrhoea is commonly known as yakka, also spelled yacca and yacka, a name probably from a South Australian Aboriginal language, mostly likely Kaurna. In the South West, the Noongar name balga' is used for X. Ĭommon names for Xanthorrhoea include grasstree, grass gum-tree (for its resin-yielding species), kangaroo tail and blackboy. The invalid Acoroides (‘ Acorus-like’ ) was a temporary designation in Solander's manuscript from his voyage with Cook, originally not meant for publication. Smith named it in 1798, from xanthos (‘yellow, golden’) and rhœa (‘flowing, flow’). Ī reference to its yellow resin, Xanthorrhoea literally means "yellow flow" in Ancient Greek. The Xanthorrhoeoideae are monocots, part of order Asparagales. Xanthorrhoea is allied to the family Asphodelaceae as monotypic subfamily Xanthorrhoeoideae. Thus, while a five-metre-tall member of the fastest-growing Xanthorrhoea may be 200 years old, a member of a more slowly growing species of equal height may have aged to 600 years. Some species grow slowly (0.8–6 cm in height per year), but increase their rate of growth in response to season and rainfall.Īfter the initial establishment phase, the rate of growth varies widely from species to species. The rate of growth of Xanthorrhoea is slow. Fires will burn the leaves and blacken the trunk, but the tree survives as the dead leaves around the stem serve as insulation against the heat of a wildfire. Flowering occurs in a distinct flowering period, which varies for each species, and often stimulated by bushfire. įlowers are borne on a long spike above a bare section called a scape the total length can be over three four metres long in some species. The trunk is sometimes unbranched, some species will branch if the growing point is damaged, and others naturally grow numerous branches. The main stem or branches continue to develop beneath the crown, This is rough-surfaced, built from accumulated leaf-bases around the secondarily thickened trunk. Plants begin as a crown of rigid grass-like leaves, the caudex slowly growing beneath. The stem may take up to twenty years to emerge. Many, but not all, species develop an above ground stem. The parenchymatous tissue is decomposed.Īll are perennials and have a secondary thickening meristem in the stem. Nutrient transport was via vascular bundles that run down the centre. Species are known by the name grass tree.ĭescription The dead "trunk" of Xanthorrhoea is a hollow ring of accumulated leaf bases. Xanthorrhoea ( / z æ n θ oʊ ˈ r iː ə/ ) is a genus of about 30 species of flowering plants endemic to Australia.
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