that they would now follow Rodd's interpretation. In his 2009 monograph on the entire genus Livistona, however, John Leslie Dowe, one of the authors mentioned, once again recognised L. rigida as an independent species, rejecting Rodd's interpretation for the time being because he had stated it was provisional, and because he noted a number of morphological differences. Research that concluded a human agency introduced the plants to the area has resulted in changes to the population's taxonomic treatment and, consequently, required reappraisal of their conservation status as a species naturalised around 15,000 years ago rather than an endemic persisting since the Miocene era. Description A palm tree with shallow roots and large hairless fronds that are slightly waxy at the underside. The height of the plant may be over twenty metres, with leaves over four metres on long petioles of a similar length. The base of the tree becomes wider and raised at an advanced age, the trunk gently tapers to a narrower width toward the crown. A description of the larger groves of this tree, which had been bypassed by the Giles expedition, was provided by a minister at Hermannsburg community. Distribution The distribution range of the nominate form is restricted to a locality known as the Palm Valley, an area where the Finke River passes through the MacDonnell Ranges. The isolated occurrence of this palm found over one thousand kilometres away from its nearest known relative at the time – the subspecies rigida – had been supposed to be a relict population. The isolation of the population was supposed to have resulted from the increased aridity of the continent since the Miocene period, around fifteen million years before the present day, or conveyed by a river or other means of dispersal. An analysis of molecular evidence found a separation from L. rigida was strongly indicated to have occurred around fifteen thousand years ago. Exclusion of other potential means for the introduction of the palm to the region, such as fruit bats or other mechanisms of distribution, left the most parsimonious explanation that it had been subject to dispersal by humans. This accords with the myths of local peoples, which allude to its deliberate introduction, the use as a resource and food, and its maintenance. Ecology In the Palm Valley a subsurface aquifer has provided constant moisture to the groves, in an area surrounded by extremes of climate, and