A bush tomato that has evaded classification by solanologists for decades has been identified and is described as a new species belonging to the Australian “Solanumdioicum group” of the Ord Victoria Plain biogeographic region in the monsoon tropics of the Northern Territory. Although now recognised to be andromonoecious, S.plastisexum Martine & McDonnell, sp. nov. exhibits multiple reproductive phenotypes, with solitary perfect flowers, a few staminate flowers or with cymes composed of a basal hermaphrodite and an extended rachis of several to many staminate flowers. When in fruit, the distal rachis may abcise and drop. A member of SolanumsubgenusLeptostemonum, Solanumplastisexum is allied to the S.eburneum Symon species group. Morphometric analyses presented here reveal that S.plastisexum differs statistically from all of its closest relatives including S.eburneum, S.diversiflorum F. Meull., S.jobsonii Martine, J.Cantley & L.M.Lacey, S.succosum A.R.Bean & Albr. and S.watneyi Martine & Frawley in both reproductive and vegetative characters. We present evidence supporting the recognition of S.plastisexum as a distinctive entity, a description of the species, representative photographs, a map showing the distribution of members of the S.eburneum species group and a key to the andromonoecious Solanum species of the Northern Territory of Australia. This new species is apparently labile in its reproductive expression, lending to its epithet, and is a model for the sort of sexual fluidity that is present throughout the plant kingdom.

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Understanding the distribution of plant species and vegetation communities is important for effective conservation planning and ecosystem management, but many parts of the world remain under-surveyed. The Top End of Australia’s Northern Territory is vast, remote, and sparsely populated; knowledge of the flora, in many areas, is limited to common or dominant species. Here, we describe and contrast the benefits and trade-offs between two approaches to botanical survey – vegetation sampling (assessment of structural attributes and species composition, fundamentally for mapping purposes) and hybrid floristic survey (an intensive, inventory approach considering seasonality) – as applied in each of four remote areas of the Australian wet–dry monsoonal tropics. Hybrid floristic survey effectively doubled the species richness recorded within each study area, largely due to improved detections of forbs and sedges. Species-sampling effort relationships predicted hybrid floristic survey to consistently out-perform vegetation sampling in maximum species richness and rate of species accumulation. Although vegetation sampling offers an efficient means of circumscribing vegetation communities over large areas, hybrid floristic survey improved detection of seasonal species and, potentially, those of conservation concern. Strategic, proactive investment in hybrid floristic surveys may offer improved conservation outcomes and potential efficiency dividends in biodiversity conservation planning.

Australia has a very diverse pea-flowered legume flora with 1715 native and naturalised species currently recognised. Tribe Mirbelieae s.l. includes 44% of Australia’s peas in 24 genera with 756 recognised species. However, several genera within the Pultenaea alliance in tribe Mirbelieae are considered to be non-monophyletic and two main options have been proposed: option one is to merge ca. 18 genera containing ca. 540 species (the largest genus, Pultenaea has nomenclatural priority); and option two is to re-circumscribe some genera and describe new genera as required to form monophyletic groups. At the species level, option one would require 76% of names to be changed; whereas based on available data, option two is likely to require, at most, 8.3% of names to change. Option two therefore provides the least nomenclatural disruption but cannot be implemented without a robust phylogenetic framework to define new generic limits. Here we present novel analyses of available plastid DNA data (trnL-F) which suggest that option two would be feasible once sufficient data are generated to resolve relationships. However, the reticulate evolutionary histories or past rapid speciation suggested for this group may prevent the resolution of all nodes. We propose targeted use of Next-Generation Sequencing technology as the best way to resolve relationships between the key clades in the tribe and present a framework for such a study. An overview of current taxonomy in the tribe is presented, along with the state of taxonomic knowledge and availability of published descriptions for electronic flora treatments. Several new combinations and typifications are published in an appendix.

The spatial extent of terrestrial vegetation types reliant on groundwater in arid Australia is poorly known, largely because they are located in remote areas that are expensive to survey. In previous attempts, the use of traditional remote sensing approaches failed to discriminate vegetation using groundwater from surrounding vegetation. Difficulties in discerning vegetation groundwater use by remote sensing may be exacerbated by the unpredictable rainfall patterns and lack of annual wet and dry seasons common in arid Australia. This study presents a novel approach to mapping terrestrial groundwater-dependent ecosystems (GDEs) by applying singular value decomposition (SVD) to time-series of vegetation indices derived from Landsat-8 data, to isolate the temporal and spatial sources of variation associated with groundwater use. In-situ data from 442 sites were used to supervise and validate logistic regression models and neural networks, to determine whether sites could be correctly classified as GDEs using components obtained from the SVD. These results were used to produce a probability map of GDE occurrence across a 557 000 ha study area. Overall accuracy of the final classification map was 79%, with 72% of sites correctly identified as GDEs (true positives) and 16% incorrectly classified as GDEs (false positives). The approach is broadly applicable in arid regions globally, and is easily validated if general background knowledge of regional vegetation exists. Globally, and going forward, increased water extraction is expected to severely limit water available for GDEs. Successfully mapping GDEs in arid environments is a critical step towards their sustainable management, and the human and natural systems reliant upon them.