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He recognized 26 Australian genera, including 95 species, mainly endemic, in a total of more than 1800 species. Most writers have continued to use Schlechters' classification of Dendrobium, combined with infrageneric and infraspecific taxa. In their treatises on Dendrobium, Upton (1989), Lavarack, Harris & Stocker (2000) and Wood (2006) all used many of the sections of Schlechter and occasionally others. Wood (2006) assembled much information on classification, with personal views and experience, in a large monograph The Dendrobiums. Many Australian Dendrobium spp. have north�Csouth distribution ranges of several thousand kilometres and knowledge of their ranges is often incomplete. Extended field exploration is required to assess the morphological characters of the most variable taxa and to identify intermediates. There have been statements that some proposed species in section Dendrocoryne (elevated from infraspecific ranks) have distinct geographical distributions and that plant forms with intermediate characters do not exist (Clements & Jones, 1990; Jones 2006). In Dendrocoryne, D. speciosum and D. tetragonum have recently been surveyed in more detail. For D. speciosum, intergrading and intermediate forms between varieties have been described in contiguous geographical areas of all four most southerly east-coast varieties, i.e. D. speciosum vars. speciosum, hillii Mast., grandiflorum F.M.Bailey and capricornicum Clemesha, and also in northern Queensland for D. speciosum vars. pedunculatum Clemesha and boreale (Adams et?al., 2006a, c;Adams, Burke & Lawson, 2006d). Some areas where D. tetragonum vars. cacatua (M.A. Clements & D.L. Jones) H. Mohr and giganteum STK38 Leaney grow together have intermediate forms with a mixture of characters, e.g. at Eungella, Queensland, as do D. tetragonum vars. melaleucaphyllum (M.A.Clements & D.L.Jones) Dockrill and tetragonum; for example, at Urunga, New South Wales (Adams, 2011). For D. kingianum, there is a continuum of habitat for ssp. kingianum along the east coast part of the distribution, with a disjunct distribution for ssp. carnarvonense at Carnarvon Gorge (Adams & Lawson, 1995). Distribution of variants of these three complexes, elevated to specific status by Clements & Jones (2002), overlap in many instances and distribution does not always assist in identification or provide evidence for specific rank. Extensions of distribution and intermediate forms have also been identified for other Dendrocoryne spp. and in the D. bigibbum Lindl. & Paxton complex. The task of surveying variation over large distributions is formidable and can lead to selective accessions, which do not represent the variability of species, and description of taxa that are not evident after more detailed study (Adams & Lawson, 1995; Adams et?al., 2006a, c, d; Burke et?al., 2008).