Archer’s sedge (Carex archeri Boott) is a small, rare (or possibly overlooked by collectors due to the diminutive size) species restricted to alpine and subalpine habitats in south-eastern mainland Australia and Tasmania. The systematic placement has been obscure with the species having been historically associated with sections in four of the six recognised Carex subgenera. We investigated the placement of C. archeri by addition to the available Carex molecular phylogenetic framework. Our results support C. archeri belonging to sect. Junciformes (in subg. Psyllophorae), making this the only representative of the subgenus in Australia. This placement was first proposed by Kükenthal (1909) who regarded C. archeri as a synonym of the New Zealand endemic C. acicularis Boott but our phylogenetic analyses support C. archeri as a separate taxon. Our approach highlights the utility of molecular barcoding for elucidating systematic relationships of poorly known taxa. Biogeographic reconstruction suggests Late Miocene dispersal from South America to the south-western Pacific but does not clarify whether New Zealand or Australia was colonised first. We evaluate the conservation status of Carex archeri using IUCN criteria as Endangered at the global level. At the state level, we propose Critically Endangered status in New South Wales, Endangered in Victoria and Data Deficient in Tasmania.

We present an annotated checklist of the 29 species comprising Syzygium subg. Sequestratum. Species in the subgenus were identified through a comprehensive review of herbarium specimens and relevant literature, including both historic taxonomic and regional revisions of Syzygium, and recent molecular phylogenetic analyses. No single character is diagnostic of subg. Sequestratum; instead, a combination of commonly occurring characters is used, including glaucescence in the hypanthium, funnel-shaped flowers <10 mm long and coriaceous leaves with dark drying petioles in contrast to a paler lamina. Species are distributed across East Asia, Malesia and Eastern Australia, with an apparent preference for nutrient-poor habitats. This checklist provides a foundation for future taxonomic revision of this clade, from an early branching node in the tree of life of the world’s largest tropical tree genus.

The Nicotiana megalosiphon Van Heurck & Müll.Arg. species complex has been shown to be composed of several morphologically cryptic species similar to N. simulans N.T.Burb. Using phylogenetic and population genetic approaches (maximum likelihood, co-ancestry, admixture proportions, Bayesian species delimitation and coalescent methods), we demonstrate that there is an additional undescribed species in this complex. The species limits of N. latifolia M.W.Chase & Christenh., N. latzii M.W.Chase, R.W.Jobson & Christenh., N. megalosiphon, N. sessilifolia (P.Horton) M.W.Chase & Christenh. and N. simulans, previously circumscribed based solely on a phylogenetic approach, are confirmed in the new analyses and a new species, N. palssonae M.W.Chase & Christenh., is described. A map of species distributions and a key to the species of the N. megalosiphon species complex are provided.