Index of chromosome numbers of Tasmanian spermatophytes

A preliminary index of chromosome numbers for spermatophytes indigenous to Tasmania is presented, with reference citations. This compilation includes reports for 166 species provenanced from Tasmanian material, many previously published, and also 55 unpublished results (mostly from the work of WDJ). Selected reports of species indigenous to Tasmania but derived elsewhere (usually material from New Zealand or the Australian mainland) are also included as a basis for further study. In total, chromosome numbers are listed for 400 species (409 taxa, including subspecies and varieties) out of a total estimated spermatophyte flora of 1568 described indigenous species. Ten of the 108 families have been examined in some detail (>45% of species), but the four most speciose families (62511568 species; Orchidaceae, Asteraceae, Poaceae and Cyperaceae) have a total of only four Tasmanian reports, despite highly variable chromosome complements. Five other speciose families (Apiaceae, Brassicaceae, Juncaceae, Rhamnaceae and Scrophulariaceae) have no Tasmanian reports despite demonstrating cytological variability at generic, inter- and intra-specific levels. Further cytological investigation of these taxa is essential for a clearer understanding of the Tasmanian flora

Phenetic affinities, variability and conservation status of a rare Tasmanian endemic Eucalyptus morrisbyi J.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, virninalis. 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