Xanthorrhoea

Xanthorrhoea (/zænθoʊˈriːə/) is a genus of about 30 species of flowering plants endemic to Australia. All are perennials and have a secondary thickening meristem in the stem. Many, but not all, species develop an above ground stem. The stem may take up to twenty years to emerge. Plants begin as a crown of rigid grass-like leaves, the caudex slowly growing beneath. 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. 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 over three four metres long in some species. Flowering occurs in a distinct flowering period, which varies for each species, and often stimulated by bushfire. 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. The rate of growth of Xanthorrhoea is very slow. However, this is often generalized to mean they all grow at the rate of about an inch (2½ cm) per year. Actually, after the initial establishment phase, the rate of growth varies widely from species to species. 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. Xanthorrhoea is allied to the family Asphodelaceae as monotypic subfamily Xanthorrhoeoideae. The Xanthorrhoeoideae are monocots, part of order Asparagales. A reference to its yellow resin, Xanthorrhoea literally means 'yellow flow' in Ancient Greek. Smith named it in 1798, from xanthos (‘yellow, golden’) and rhœa (‘flowing, flow’).The invalid Acoroides (‘Acorus-like’) was a temporary designation in Solander's manuscript from his voyage with Cook, originally not meant for publication. In the South West, the Noongar name balga' is used for X. preissii. 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.