The current tribal classification of Myrtaceae was based on analysis of the plastid matK coding region within the trnK intron. The phylogenetic position of the genera Cloezia and Xanthomyrtus was poorly supported, and the original sequence for Kania, the type genus of the tribe Kanieae, was rather poor. To clarify relationships, we sequenced plastid psbA–trnH and an extended portion of the trnK intron, including the spacer regions flanking matK, and nuclear ribosomal ITS and ETS regions for representative species across the tribes, including denser sampling of the three genera of interest. Analyses of these extended datasets show a strong relationship between Kania and the tribe Metrosidereae but not with other genera presently assigned to the Kanieae. The relationship between Kania and the tribe Metrosidereae is strongly correlated with morphological features recently documented in Metrosideros fossils. Consequently, a new tribe, Tristaniopsideae PeterG.Wilson, is described to accommodate most genera presently assigned to Kanieae. Furthermore, the morphological divergence and genetic distance shown by Cloezia and Xanthomyrtus are here considered as justifying their recognition as the tribes Cloezieae Peter G.Wilson and Xanthomyrteae Peter G.Wilson. Recognition of these tribes brings to four the number of tribes absent from present-day mainland Australia. Prior to this study, Metrosidereae was the only tribe in subfamily Myrtoideae that was absent from mainland Australia.

The South American genus Praxelis Cass. (Asteraceae, Eupatorieae) includes 18 species and is the second-largest genus of subtribe Praxelinae. It is distributed from Colombia, Venezuela and the Guianas, to central Argentina, southern Brazil and north-western Uruguay. Over the past 40 years, one species, P. clematidea, has invaded several countries around the world. To understand Praxelis and its species, this study provides an updated taxonomy with the re-establishment of P. urticeafolim var. nanum as a synonym of P. ostenii, 16 lectotypifications, clarification of morphology and geographical distribution, brief descriptions, and the first key to all the species in the genus.

Variation in breeding systems between species of the same taxonomic group complicates the consistent application of species concepts, and perhaps even the logically consistent circumscription of species. Several genera of arid-zone ephemerals in the Angianthus clade (Asteraceae: Gnaphalieae: Gnaphaliinae) contain both outcrossing and non-outcrossing species. The latter are recognised by producing an order of magnitude fewer pollen grains per anther and an often reduced number of corolla lobes, and they are frequently more widespread than are the former. In its current taxonomy, the genus Pogonolepis comprises an otherwise morphologically indistinguishable pair of one outcrossing and one non-outcrossing species. I generated sequence capture data to test the genetic segregation of P. stricta and P. muelleriana and the utility of sequence capture data for species circumscription and diagnostics. Phylogenetic analysis showed the two species to form two specimen clades, supporting the current taxonomy. Contrary to expectations, non-outcrossing P. muelleriana exhibited lower gene concordance, in line with values expected from recombination, as well as higher heterozygosity than its outcrossing sister species. More research on the breeding system and population structure of the two species may be required to explain these results.

Philotheca sect. Erionema includes 14 species from eastern Australia and one from south-western Australia. We conducted a phylogenetic analysis of the section, including samples of all species, using sequences of the ITS and ETS regions of nuclear ribosomal DNA. Results were broadly congruent with a previous analysis based on morphological and flavonoid data. The analysis is consistent with the monophyly of the section and supports the monophyly of six species represented by multiple samples. Philotheca verrucosa (A. Rich.) Paul G. Wilson was resolved as paraphyletic with respect to P. freyciana Rozefelds but with poor support. Philotheca glasshousiensis, P. myoporoides and P. myoporoides subsp. myoporoides were clearly polyphyletic, including separate geographic clades and the classification of each of these taxa requires revision. In particular, disjunct northern populations of P. glasshousiensis probably represent a distinct species, the five subspecies of P. myoporoides could be treated as separate species and at least two other distinct groups that are currently included under the circumscription of subsp. myoporoides could be treated as species. The phylogeny revealed deeply divergent, geographically overlapping clades in eastern Australia and substantial distances (up to 900 km) between sister taxa. We infer that biogeography of the group has been shaped largely by vicariant differentiation of taxa.