Phenetic affinities, variability and conservation status of a rare Tasmanian endemic Eucalyptus morrisbyi R.G.Brett

Eucalyptus morrisbyi is a rare Tasmanian endemic confined to one larger population (c. 2000 mature individuals) and two smaller populations (c. 15 and 16 mature individuals) in southeastern Tasmania. Morphological studies within the informal superspecies "Gunnii" reveal Eucalyptus morrisbyi has closest affinities to low altitude populations of E. gunnii In southeastern Tasmania and yet has distinct, phenetic differences from that species. Levels of variation in E. morrisbyi populations appear comparable to other species despite their small population size. A low frequency of hybridisation occurs with E. viminalis in natural stands but is unlikely to have affected the level of variability in the Calverts Hill and Risdon Hill natural populations. In contrast, it is shown that a high frequency of seedlings grown from a planted and a remnant stand of E. morrisbyi have affinities with E. viminalis. Several of the planted trees appeared to be hybrids and some progeny from phenotypically normal trees also appeared to be of hybrid origin. These results suggest that the genetic integrity of the species may be compromised by injudicious selection of seed for propagation from plantings and could be a major problem for the ex situ conservation of this and other rare and endangered species. Recommendations are given to enhance the conservation of this endangered Tasmanian endemic.