Melichrus urceolatus

Melichrus urceolatus View in CoL and M. erubescens

Melichrus urceolatus View in CoL has been maintained as a species through various treatments, albeit with differing limits. Paterson circumscribed M. urceolatus View in CoL to include a vast geographical area; from Herberton, northern Queensland to Saint Arnaud, Victoria, acknowledging that ‘within this range a large variety of form is shown…’ ( Paterson 1958, p. 313). Paterson (1958) provided a brief description of five groups that differed morphologically from the ‘typical condition’ and the approximate geographic range but did not attempt formal subdivision ( Paterson 1958, p. 313). A great deal of this variation was noted to occur in Queensland, where three phrase-named putative species have been accepted by the APC (CHAH, accessed 4 May 2023), namely M. sp. Inglewood (A.R.Bean 1652), M. sp. Isla Gorge (P.Sharpe + 601) and M. sp. Tara (D.Halford Q2259).

Several putative species have been segregated from Melichrus urceolatus View in CoL and informally phrase-named at the N.C.W. Beadle Herbarium (NE) but are not yet listed on the APC, including M. sp. Mareeba (H.T. Kennedy 92) NE Herbarium, M. sp. Galambary (H.T. Kennedy 7) NE Herbarium, M. sp. Gilgandra (H.T. Kennedy 128) NE Herbarium, M. sp. Gardens of Stone (H.T. Kennedy 46) NE Herbarium and M. sp. Salvator Rosa (M.B. Thomas 244) NE Herbarium that were identified during exploratory herbarium and field observations made in the early stages of this study.

Paterson (1958) retained the synonymy of Melichrus medius under M. urceolatus established by Bentham, explaining that no difference was observed in the protologue descriptions or subsequent collections made from the type localities. Improved access to the type specimen and other early collections allows the original definition of M. medius to be considered anew in this study.

Paterson reinstated Melichrus erubescens to species status, explaining that ‘the taxonomic differences are such as to justify specific rank, although the two species [ M. urceolatus and M. erubescens ] are undoubtedly closely related’ ( Paterson 1958, p. 310). As currently delimited, the boundary between M. urceolatus and M. erubescens is unclear. Melichrus sp. Gardens of Stone, M. sp. Gilgandra and M. sp. Galambary, though treated as M. urceolatus by Paterson, all share morphological affinities with M. erubescens , exemplifying the unworkable boundary between the species as currently described.

Several populations of Melichrus that are morphologically similar to both M. erubescens and M. urceolatus have been collected for the first time since Paterson’s revision. These gatherings cannot be confidently assigned to either species and have been given the phrase names M. sp. Silent Grove (H.T. Kennedy 33) NE Herbarium and M. sp. Kaputar (H.T. Kennedy 25) NE Herbarium ( Table 1). A key aim of this study was to decisively clarify the boundary between M. erubescens , M. urceolatus and morphologically similar putative species M. sp. Inglewood, M. sp. Isla Gorge, M. sp. Tara, M. sp. Gardens of Stone, M. sp. Gilgandra, M. sp. Galambary, M. sp. Silent Grove and M. sp. Kaputar.