Micropholis guyanensis (A.DC.) Pierre is a tree from the rainforests of tropical South America and includes two recognised and one informal subspecies. The species has a wide geographic distribution from Central America, northern and western South America to Amazonia and Bolivia, and is morphologically variable. All subspecies occur in the Reserva Florestal Adolpho Ducke just outside Manaus, Amazonas State in Brazil, and it can be questioned how they can grow in sympatry and retain their identity. We have studied vegetative variation, flower morphology and, to some degree, reproductive barriers. The species is dioecious, has five-merous, cream to greenish flowers that produce pollen, nectar and scent to attract pollinators. The flowering period is between June and October, and the plants set fruits, one seed in each, between November and April. There was no overlap in flowering period in the study area between two of the presumed subspecies, but both have similar floral morphology and are pollinated by the same species of butterflies and bees. We are not able to find any clear distributional or morphological discontinuities between the subspecies and we, therefore, suggest that M. guyanensis should be considered a variable species without formally recognised subspecies. Flowers of M. guyanensis are highly ephemeral and persist only for 1 day (∼27 h) before falling to the ground. We predict that this is typical for many species of Sapotaceae, which can explain why the corolla is missing from the majority of herbarium specimens that at first sight have flowers.

Triodia bunicola (S.W.L.Jacobs) Lazarides and T. scariosa N.T.Burb. (Poaceae: Chloridoideae) were analysed to test their status as different species. Thirty-one morphological characters were scored for multivariate analysis for both species. Nuclear (ITS) and chloroplast (rpl32–trnL) DNA data were analysed cladistically for 18 species of Triodia, with a focus on species from southern Australia to look at broader geographic patterns. Cladistic analysis and morphological ordination analysis indicated that T. bunicola should be regarded as a synonym of T. scariosa. DNA evidence also suggests that there is geographic partitioning for southern Australian species of Triodia.

Previous estimates of phylogeny in the Phyllanthaceae, Phyllantheae, have been hampered by undersampling of species from morphologically distinctive groups and using too few gene regions. To increase the phylogenetic resolution, sequences of two nuclear (ITS1–5.8S–ITS2) and Phytochrome C (PHYC)) and two non-coding chloroplast (accD–psaI, trnS–trnG) DNA markers were analysed using maximum parsimony and Bayesian inference with expanded sampling in Breynia, Glochidion, Sauropus and Synostemon. Our results supported reinstatement of Synostemon, previously included in Sauropus s.str., to generic rank, and provided evidence towards its future infrageneric classification. The results also indicated expansion of Breynia to include Sauropus s.str.; this combined monophyletic group consists of two strongly supported clades. Finally, we showed monophyly for Glochidion, which is sister to Phyllanthus subg. Phyllanthodendron, both still remaining undersampled. Morphological features characteristic of Breynia, Sauropus and Synostemon are discussed, as well as the desirability of dividing Phyllanthus into smaller genera.

Molecular systematics has clarified the limits of Loganiaceae (Gentianales), the tribal circumscriptions and the phylogenetic relationships within the family. Loganieae includes seven genera; however, generic boundaries remain untested and intergeneric relationships are largely unknown. The chloroplast intron petD and the nuclear ribosomal ETS were sequenced for 37 ingroup accessions, including all genera of Loganieae, to infer generic and infrageneric boundaries and intergeneric relationships within the tribe. Maximum parsimony and Bayesian analyses resolved several strongly supported clades. Mitreola s. str. was placed sister to the rest of Loganieae. The south-western Australian endemic, Mitreola minima B.J.Conn, was placed sister to Mitrasacme, Schizacme and Phyllangium, rendering Mitreola polyphyletic. Mitrasacme, Logania section Logania and L. section Stomandra were each strongly supported as monophyletic, but there was no support for the monophyly of Logania. Geniostoma was paraphyletic with respect to a monophyletic Labordia. It is here recommended that Mitreola minima be afforded generic status and that the three species of Labordia used in the present study be reduced to synonymy of Geniostoma. Additional sampling is needed to clarify the relationship between Logania section Logania and L. section Stomandra and to increase support for intergeneric relationships in Loganieae.

Prostanthera is the largest genus of Lamiaceae in Australia and was last comprehensively revised in 1870. To test the classification, and the homology of the morphological characters on which it is based, we analysed nuclear (ETS) and chloroplast (trnT–F and ndhF–rpl32) sequence data for 71 species of Westringieae (Lamiaceae) in separate and combined datasets by using maximum-parsimony and Bayesian-inference methods. Results supported the monophyly of the Westringieae, but indicated that Prostanthera is paraphyletic with respect to Wrixonia, requiring the latter to be synonymised with the former. Although combinations of datasets provided some degree of infrageneric resolution within Prostanthera sensu lato, none of its sections or series could be recovered unambiguously. Prostanthera section Prostanthera and P. section Klanderia (regarded as entomophilous and ornithophilous, respectively) did not form a sister relationship, and neither could be unequivocally resolved as monophyletic. However, all species of P. section Klanderia nested within P. section Prostanthera raising the possibility that P. section Prostanthera is paraphyletic. Similarly, the phylogeny of Prostanthera based on molecular data could not be reconciled with the morphological definition of the traditionally recognised series. We recommend abandoning Bentham’s series as a means of organising morphological variation within the genus, but acknowledge that it is premature to discard Bentham’s sections. The evolutionary and systematic implications of the lack of congruence between our molecular phylogeny and morphologically defined subgeneric taxa are discussed.

Phylogenetic analyses of DNA-sequence data have revealed that the southern hemisphere species of Veronica are derived from within the northern hemisphere Veronica clade. Previous analyses focussed on the species in New Zealand and included at maximum 7 of 23 species of section Labiatoides from Australia. In the present study, we used nuclear ribosomal-ITS and plastid ndhF–rpl32-spacer sequence data of all species currently recognised in Australia to analyse phylogenetic patterns. Most importantly, herbaceous species from coastal calcareous sands or limestone habitats do not form a clade with those from shady, moist forest habitats, as formerly believed, but seem to be independently derived from woody species. Incongruence between results from nuclear- and plastid-DNA markers suggest hybridisation to be an important factor in the evolution of the group. Our sample of V. parnkalliana included alleles similar to V. decorosa and V. novae-hollandiae at both loci, which suggests a hybrid origin.

Morphological comparisons and molecular phylogenetic analyses were conducted to resolve taxonomic confusion in Cassytha glabella and C. pubescens, both of which were first described from Australia and subsequently considered to be disjunctly distributed between Australia and the Ryukyu Archipelago of Japan. In the morphological comparisons, plants considered as C. pubescens in the Ryukyus differ from C. pubescens in Australia in the presence or absence of hairs on the petals, and those considered as C. glabella in the Ryukyus differ from the C. glabella in Australia in bract and peduncle morphology. The molecular analyses indicated that plants attributed to C. pubescens in the Ryukyus were not closely related to C. pubescens in Australia, and were nested in a clade of populations of a Pan-Western Pacific species C. filiformis. Plants attributed to C. glabella in the Ryukyus were distantly related to C. glabella in Australia. We concluded that plants considered as C. pubescens and C. glabella in the Ryukyus are to be respectively treated as C. filiformis and the Ryukyu endemic species C. pergracilis.