The most recent review of the genus Gompholobium Sm. (Fabaceae: Mirbelieae), published in 2008, considered Gompholobium nitidum Sol. ex Benth. to exhibit a high degree of variation, ranging from very compact shrubs with linear leaflets, to open shrubs of a taller stature with lanceolate leaflets, through to dense shrubs with oblong leaflets with obtuse-emarginate apices. We use morphological and ddRAD sequencing data to recognise three species from this broad complex, linked with topographic and edaphic complexity in the study area (Laura south to the Atherton Tablelands, north-east Queensland): (1) G. nitidum sens. strict. is a narrowly distributed taxon limited to the white sands of coastal dunes north of Cooktown, with a single disjunct population south of Cooktown; (2) a novel species described here, G. cinctum M.T.Mathieson & C.L.Simmons, has a slightly broader distribution across the skeletal sandy loams of sandstone formations in the Cooktown region; and (3) G. papuanum Merr. & L.M.Perry, previously subsumed into G. nitidum, is reinstated and occurs broadly across north-east Queensland in woodlands from west of Townsville to Cape York, the Torres Strait Islands and into Papua New Guinea.

Chamelaucieae is a diverse tribe in Myrtaceae with ~800 species in 37 genera distributed across Australia. We applied target capture sequencing using the Angiosperms353 probe set for 131 taxa as part of the Genomics for Australian Plants initiative. Sampling all genera (36) from 10 of 11 named subtribes, we present a phylogenomic analysis for the tribe. This phylogenomic approach has allowed us to better resolve subtribal relationships across the tribe, resulting in an updated classification and additional subtribe (total of 12 subtribes including Triplarininae). Despite these advances, the phylogenetic placements of Stenostegiinae, Astarteinae, and Micromyrtinae remain equivocal and resolution of these relationships should be a focus of future research. We constructed a dated phylogeny from this genomic dataset to investigate the tribe’s biogeographic history and diversification dynamics. We estimate that the crown radiation occurred in the Eocene (c. 42 Ma), with the ancestral area of origin in Australia unresolved. Subsequent divergence and origin of subtribes mostly occurred in south-west Western Australia with frequent dispersals from there into the semi-arid and arid interior since the Miocene (20 Ma). Dispersals out of northern and eastern Australia were limited and confined to dispersal events into the arid interior. Using paleoenvironmental diversification models we show that after the initial radiation, diversification in Chamelaucieae declined rapidly until the Eocene–Oligocene boundary extinction pulse event and subsequently more slowly to the present, with a modest increase during the Middle Miocene Climatic Optimum. No significant diversification rate shifts were detected within clades except within the subtribe Chamelauciinae. There was no significant geographic-dependent diversification in the tribe. Our results add to the growing literature revealing that high plant diversity in south-west Western Australia is due to more time for species accumulation attributed to long-term climatic stability rather than elevated diversification rates.

Leaf fossils collected in 1908 from the Arauco–Concepción Coal Measures of Chile (the Lota–Coronel flora) during a Swedish expedition to southern South America are formally assigned to the important Gondwanan family Proteaceae as Proteaceaefolia araucoensis R.J.Carp. & McLoughlin gen. nov., sp. nov. This is the oldest South American record of macrofossils that can be assigned to Proteaceae with confidence due to the likelihood of the age dating to the latest Paleocene. The fossils lack cuticle but the large, lobed and minutely toothed form is consistent only with extant species of the subfamily Grevilleoideae (notably, Orites excelsus R.Br.) that are confined to eastern Australian rainforests. A new assessment of the Swedish Lota–Coronel collection and review of previous palynological and macrofossil studies, also provide evidence of the strong biogeographic connection that existed between southern South America and Australasia during the early Paleogene, and contradict a traditional view that several Chilean floras of this age consist wholly or largely of Neotropical taxa. Notable austral taxa include Casuarinaceae (as abundant pollen), diverse Podocarpaceae (as both foliage and pollen) and likely Cunoniaceae (leaves). No taxa with clearly Neotropical nearest living relatives have been found to date, but previous conclusions for a warm and very wet early Paleogene climate are supported.

Zieria obcordata A.Cunn. (Rutaceae), an endangered species endemic to central New South Wales, Australia, faces significant conservation challenges due to limited occurrence in two small, isolated populations. Using genome-wide SNPs (DArTseq), we examine genetic relationships and diversity within and between these populations, and make comparisons with other Zieria species. Our results confirm that Z. obcordata is a distinct species, with the Bathurst and Wellington populations showing sufficient genetic divergence to warrant recognition as two subspecies: Z. obcordata subsp. obcordata and Z. obcordata subsp. wuuluman (formally described here). Minor morphological differences further support this classification. Genomic analyses reveal minimal gene flow between the subspecies, along with extremely low heterozygosity and high inbreeding coefficients within each. Compared to other Zieria species, including Z. covenyi, Z. cytisoides, Z. laevigata, Z. odorifera and Z. smithii, both subspecies exhibit exceptionally low genetic diversity, likely due to geographic isolation, genetic drift and inbreeding. We provide conservation assessments for both subspecies and conclude that each qualifies to be listed as Critically Endangered under the New South Wales Biodiversity Conservation Act 2016. We recommend strategies to facilitate gene flow between the subspecies to improve genetic diversity and enhance fitness.