Standing on the shoulders of giants: molecular data confirm Kükenthal’s systematic placement of the Australian endemic Carex archeri (Cyperaceae)

Abstract

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.