Although some authors previously questioned the circumscription of Nicotiana benthamiana, it has never been treated taxonomically as more than a single widespread, variable species. A recent study employing phylogenetic and population genetic analyses has demonstrated that N. benthamiana comprises five species that are geographically and morphologically distinct. Here, we describe four new species in the N. benthamiana complex, namely, N. bilybara M.W.Chase & Christenh., N. candelabra M.W.Chase & Christenh., N. rupestris M.W.Chase & Christenh. and N. scopulorum M.W.Chase & Christenh., and illustrate all five. We provide descriptions, a diagnostic key and a table of morphological characters distinguishing these closely related species. The major morphological feature that distinguishes N. benthamiana from the other four species is its petiolate leaves that become sessile only near the apex of the inflorescence; N. candelabra is distinct in its bifacial branching, N. bilybara in its commonly winged petiole with an auriculate base, N. rupestris in the leafy apices of its calyx lobes, and N. scopulorum is the least morphologically divergent species, conforming most closely to the general description of the N. benthamiana species complex.

Statistical analyses of two morphological datasets, including 190 newly measured specimens, showed that individuals of Myosotis (Boraginaceae) from Te Waipounamu / South Island, Aotearoa, New Zealand, identified a priori with three different informal tag names, belong to the bracteate–prostrate group, are morphologically distinct from each other and from other species, and merit scientific description. Myosotis hikuwai Meudt, Prebble & G.M.Rogers is known from one location near Wānaka (Otago), has an unusual erect, spring annual habit, and is most similar to M. brevis and M. glauca, with which it is sympatric. Myosotis venticola Meudt & Prebble comprises plants that were sometimes previously identified as M. cheesemanii from certain ranges in Otago and southern Canterbury, but with retrorse trichomes present on the abaxial and adaxial side of the rosette leaves. Myosotis ultramafica Meudt, Prebble & Rance comprises individuals from ultramafic sites in certain ranges in Southland, and is most similar to M. cheesemanii and M. lyallii. We recommend that all three new species are listed as Threatened under the New Zealand Threat Classification System. In addition to descriptions and illustrations, the three new species are also included in a revised key to the nineteen species of southern hemisphere bracteate–prostrate Myosotis.

Crinum flaccidum Herb. is widespread across southern and eastern Australia, but suffers from taxonomic uncertainty. This ambiguity is in part due to widespread hybridisation in the genus, but also morphological variability within and among populations. Morphological and molecular analyses of the complex using 24 morphological characters and 59 chloroplast coding and non-coding regions (~50 000 bp) provided support for the separation of C. flaccidum from C. luteolum Traub & L.S.Hannibal ex Traub, with the latter representing populations from the Flinders Ranges and Lake Eyre Basin. Within Crinum flaccidum, there was greater inferred genetic structure at the population level for New South Wales flood plain accessions, compared with South Australian populations from along the Murray River. The greater structure of the South Australian populations is theorised to be attributed to lower seed-dispersal rates leading to lower gene flow.

To investigate the relationships among species in the taxonomically problematic Eucalyptus odorata species complex, we generated molecular data using double-digest restriction site-associated DNA sequencing (ddRADseq) and Diversity Arrays Technology sequencing (DArTseq). These data were analysed utilising principal-component analysis (PCA), phylogenetic networks, phylogeny reconstruction and hybridisation tests. Twelve species that are variously recognised in the complex were sampled from across their ranges, along with co-occurring members of E. section Adnataria, to allow for patterns of hybridisation and gene flow to be identified. Despite the large genetic datasets generated, many relationships within the E. odorata complex were poorly resolved, and few species were monophyletic, likely owing to both biological factors including recent speciation and extensive hybridisation and introgression, and potential over-splitting of taxa. We show that multiple taxa with limited distributions are the result of reticulate evolutionary events and that typical Eucalyptus viridis R.T.Baker and the possibly con-specific E. aenea K.D.Hill are sister to the rest of the complex. The remaining species appeared to represent a discontinuous crescent-shaped cline running from the Flinders Ranges to the south-western slopes region of New South Wales, with limited support for an east–west split in this cline across the Murray River Basin. Eucalytpus viridis var. latiuscula Blakely, which is not closely related to the typical variety of this species in our data, may represent a northern extension to this cline.