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Haloragis exalata F. Muell. subspecies exalata (family Haloragaceae), a perennial forb, is currently listed as Vulnerable, under both national and New South Wales threatened species conservation legislation. Very few herbarium records existed until recently. Recent discoveries of Haloragis exalata subsp. exalata in new sites on the NSW South Coast and Southern Tablelands prompted us to carry out surveys for the two varieties of the taxon, var. exalata and var. laevis. Our surveys in 2004– 2007 aimed to relocate historical collection sites and target areas of potentially suitable habitat in these areas. Our work has substantially increased the number of known localities for Haloragis exalata subsp. exalata var. exalata. It can be locally abundant. Ecologically it appears to function as a gap species whose populations are almost invariably found at sites where disturbance through temporary inundation, physical disturbance, or fire, has exposed bare earth with higher levels of light at ground level than would be present when the local vegetation community is intact. There are morphological differences between populations in disjunct areas. Haloragis exalata subsp. exalata var. laevis is much more restricted. As a result, the conservation status of Haloragis exalata subsp. exalata may need revision, considering that a) var. exalata is more widespread than previously known, but that b) there is only one known extant population of var. laevis, and that c) the population from Geehi area may be a distinct taxon.
An exhaustive review of available information revealed 1522 native vascular plant taxa with confirmed records in the Eden region. A further 136 taxa potentially occur in the region, but these remain to be confirmed. Families represented by large numbers of taxa in the indigenous flora include the Fabaceae, Poaceae, Asteraceae, Myrtaceae and Orchidaceae. Species frequencies were highly skewed with 74% of the flora represented in less than 1% of survey samples and only three taxa represented in more than 40% of samples. A large number of records (350 taxa) were evaluated and refuted, emphasizing the importance of critical validation when compiling biological inventory data from multiple sources. Errors are most likely to arise from nomenclatural synonymy and other duplications, misidentifications and erroneous locality information.
The confirmed vascular flora of the Eden region is relatively species-rich compared with other regions in tropical, temperate and semi-arid Australia, although these regions are less well-known botanically. However, the proportion of endemism (1%) is comparatively low, with 18 taxa unique to the region and a further 14 taxa with distributions extending just beyond the region. The Eden region includes 32 taxa listed as endangered or vulnerable in Australia and a further six taxa listed as endangered in New South Wales but not throughout Australia. Thirty-eight taxa were listed as rare in Australia and a further 39 were considered to be uncommon throughout their distribution. Four hundred and sixty-six taxa were considered to be uncommon within the Eden region. Two hundred and seventy-six taxa reached their distributional limits in the Eden region, about three quarters of these reaching their southern limits. Fifty taxa were represented in the region by disjunct populations.
Introduced taxa accounted for approximately 20% of the total regional vascular flora, although this proportion is likely to underestimate the introduced flora given the limitations of available data. The introduced flora is dominated by Poaceae, Asteraceae, Fabaceae and Caryophyllaceae. Very few introduced taxa were widespread in native vegetation. The most common introduced taxa were herbs with long-distance propagule dispersal mechanisms.