Camel melon (Citrullus lanatus), colocynth (Citrullus colocynthis) and prickly paddy melon (Cucumis myriocarpus) are summer-growing invasive weeds distributed throughout Australia. We used DNA-sequence information from samples collected across Australia and morphological data from glasshouse-grown plants to determine diagnostic features of these species, and to determine the infraspecific identity of Australian Citrullus lanatus and Cucumis myriocarpus. All species possessed distinct genotypes and haplotypes at nuclear G3pdh and chloroplast ycf6–psbM gene regions and could be easily identified on the basis of molecular phylogenetic analysis. A combination of vegetative, floral, fruit and seed characters also allowed for species identification at all developmental stages. On the basis of our morphological and molecular analyses, Australian camel melon and prickly paddy melon populations were identified as Citrullus lanatus var. citroides and Cucumis myriocarpus subsp. myriocarpus respectively.

We used nuclear rDNA-sequence data from the internal transcribed spacer (ITS) region to test the monophyly of Schoenus by using maximum parsimony and Bayesian inference. Schoenus is not monophyletic, with strong bootstrap support for most branches and congruence across analyses. nrITS does not resolve terminal taxa fully and, therefore, needs to be used in combination with other lines of evidence to address questions of species limits.

Australia supports a high diversity of sequestrate (truffle-like) macrofungi. This has long been thought to be related to the predominantly or seasonally dry climate. The present study posits that if aridity were a key factor in the evolution of sequestrate fruit-bodies, most sequestrate species would have emerged in Australia only after it began to aridify, which occurred post-separation with Antarctica (c. 32 million years ago). Focusing on the high phylogenetic diversity of sequestrate taxa in the Agaricomycetes in Australia, dates of sequestrate nodes were compiled directly from published phylogenies (four lineages) or created using sequences available on GenBank that were processed in BEAST using a secondary calibration method (nine lineages). Although the morphologically diverse Hysterangiales was found to be the first group to become sequestrate, c. 83 million years ago, overall sequestration in Australia occurred more recently. Models were created and compared and support was found for an increased rate of sequestration in Australia at some point between 34 and 13 million years ago (during the Oligocene and Miocene). Although the rate of sequestration is shown to have increased in Australia after separation from Antarctica, the timing also overlaps with the radiation of potential mycorrhizal plant associates, and the emergence of specialised mycophagous marsupials. Although aridification is evidently not the sole driver of sequestration, it is still likely to have had a major influence on the diversity of sequestrate fungi in Australia. Comparisons with other regions of high sequestrate diversity will be informative.

Cookson (1950) erected the fossil pollen genus Banksieaeidites to accommodate palynomorphs with characters resembling those of the extant Proteaceae genus Banksia. One of the most commonly reported species, Banksieaeidites arcuatus Stover & A.D.Partr., is now known to more closely resemble pollen of the Proteaceae subtribe Musgraveinae, than that of subtribe Banksiinae. The late Eocene Mulga Rock deposits in the southern Officer Basin of Western Australia have yielded palynofloras that contain up to 7% of two new species that can confidently be aligned with pollen of modern Banksia. Banksieaeidites davidsonii sp. nov. and B. rugulus sp. nov. are formally described, and pollen from eight extant Banksia are described and compared with the two fossil species. The variation in extant Banksia L.f. pollen morphology, and that between the two Banksia subgenera (B. subgenus Banksia and B. subgenus Spathulatae A.R.Mast & K.R.Thiele) are discussed, and the changes in the morphology of Banksia pollen grains as they mature are reported.

This is the first integrative synopsis of the genus Atriplex L. for South America, based on the study of compared external morphology of extensive collections from South American herbaria, type material, digital images, original publications and field observations. The South American Atriplex flora includes 55 species, 45 of which are native species, mainly distributed in Argentina and Chile (a few of them growing in Bolivia, Ecuador, Paraguay, Peru, Uruguay and Venezuela), and 10 are adventive species. We accept two subspecies for Atriplex cordubensis Gand. & Stuck., namely, subsp. cordubensis and subsp. grandibracteata Múlgura, two varieties for A. imbricata D.Dietr., var. imbricata and var. foliolosa Rosas, proposed one new synonym for A. deserticola Phil., one nomenclatural change for A. mucronata Phil., and designate 19 lectotypes and one second-step lectotype for A. nummularia Lindl. This synopsis also includes a key to the 55 South American species, three new figures for A. asplundii Standl., A. oestophora S.F.Blake and A. rusbyi Britton, references for previous figures of the remaining species, illustrations of different positions of the radicle in the seeds, maps of distribution, taxonomic and morphological notes, and a complete list of material studied.

Molecular and morphological data support the recognition of seven species of Chiastocaulon in Australia, of which four, namely C. braunianum and C. geminifolium comb. nov. from tropical north-eastern Queensland and C. proliferum and C. flamabilis sp. nov. from Tasmania (and New Zealand), represent new records. The other three species accepted for Australia are C. biserialis, C. dendroides and C. oppositum. Chiastocaulon conjugatum is excluded from the Australian flora, because previous Australian records are based on misidentifications of C. braunianum and Plagiochila retrospectans. Pedinophyllum monoicum, reported for Australia from a single locality in Victoria, is excluded from the Australian flora because all credible records are based on misidentifications of Syzygiella tasmanica. The Papua New Guinean Chiastocaulon takakii comb. nov. is reinstated from synonymy under C. dendroides on the basis of morphological evidence. Descriptions and illustrations of all Australian species, and dichotomous keys to species of the Chiastocaulon lineage in Australia and New Zealand, are provided.