Xanthorrhoea is a genus of flowering plants in the Asphodelaceae family native to tropical and subtropical Australia. Plants in this genus were once considered to be part of the Liliaceae family. Species are perennial plants with thick woody stems varying from mainly subterranean, not appearing above the ground, to rather tall and arborescent, branched or unbranched. In spite of being monocots they are not geophytes or bulbs in the usual sense even though a number of species occur in areas of Australia where they survive a period of time without regular rainfall. Some of the species have root tubers that are produced annually, especially when the plants are young. Flowers are borne on a long spike (scape). For a number of the species flowering is stimulated by fires. Plants can be grown from seed and can be attractive garden plants.
Xanthorrhoea australis grows in Victoria, in South Australia, the southern coast of New South Wales and Tasmania. This species is not often seen in bloom unless fires has stimulated its reproductive cycle. It has leaves that are softer and less rigid than some of the other species. Plants that have burned have black trunks with grass like leaves forming a skirt. It grows up to 3 meters. Flowers of this species have six petals. Photos taken by Mary Sue Ittner and Bob Rutemoeller October 2007 in the Grampians where there had been fires earlier so there was a good display of flowers.
Xanthorrhoea preissii grows in Western Australia in various habitats. It has an upright trunk and can reach 5 meters with a trunk of over 3 meters. It has yellow root tubers that are ephemeral lasting from April till January. Plants bloom between August and November with flowering enhanced if plants have burned the previous summer. The spike can be 1 to 3 meters high with numerous flowers crowed on the upper part of the scape. Photos taken by Bob Rutemoeller and Mary Sue Ittner September 2007 in southwestern Western Australia show plants and flowers as they open on the spike and are pollinated.
Xanthorrhoea sp. This photo from Mary Sue Ittner was taken on the Great Ocean Walk near Apollo Bay, Victoria, October 2007. It could be just a smaller plant of Xanthorrhoea australis that has yet to grow a trunk, although there is a species called Xanthorrhoea minor that grows in Victoria that does not have a trunk.