— Evolutionary trends and phylogenetic relationships in the Strelitziaceae (Zingiberales) were investigated using sequence data from ten plastid and two nuclear regions and a morphological dataset. The status of species of Strelitzia were evaluated in terms of the phylogenetic species concept. Relationships among the genera remain equivocal with two hypotheses emerging: (i) Strelitzia sister to a clade comprising Ravenala and Phenakospermum when indels are included, or (ii) Ravenala sister to the remainder of the Strelitziaceae when indels are excluded in/from the combined molecular and ‘total evidence’ analyses. Within Strelitzia, S. nicolai is sister to the rest of the genus, with S. alba sister to S. caudata. Strelitzia reginae is shown to be paraphyletic as S. juncea is nested within it, but more sampling at the population level is needed to confirm the taxonomic status of S. juncea. The highly localized and endangered Strelitzia alba is confirmed as a distinct species, as are S. caudata and S. nicolai, despite few morphological differences. Evolutionary trends are linked to changes in habitat and coevolution with pollinators. Climate change in southern Africa is thought to have restricted Strelitzia nicolai (or its ancestor) to the eastern coastal region, with subsequent allopatric speciation of S. alba and S. caudata, and relatively recent parapatric divergence of S. juncea from S. reginae.

Heavy metal polluted soils can be remediated using plants, a process called phytoremediation. However, high concentrations of heavy metals can negatively affect plant physiology and growth. We experimentally evaluated the effects of cadmium (Cd) on the growth, (i.e. height, shoot and biomass) and physiology (i.e. leaf chlorophyll and relative water contents) of Tamarix usneoides. In a greenhouse experiment, T. usneoides clones were subjected to a once off treatment of 100 mmol/l NaCl with three different Cd concentrations (6, 12, and 18 mg/kg) applied 3 times/week for eight weeks. We predicted that plant health would decrease with an increase in Cd concentration. Results revealed a 35.9% reduction in chlorophyll content between the 18 mg/kg Cd treated plants and the control, suggesting that T. usneoides experienced a reduction in photosynthetic rate, which in turn influenced the growth and relative water content (RWC) of the plant. Although T. usneoides’ growth and physiology were significantly decreased at 12 and 18 mg/kg Cd concentrations, the plants tolerated up to 6 mg/kg Cd concentration, a level found in most anthropogenic Cd-contaminated soils. Tamarix usneoides should thus be confirmed as a good phytoremediation candidate once its ability to extract, translocate and concentrate Cd has been determined.

Emilia is a widely distributed, mainly African, palaeotropical genus in the tribe Senecioneae (Asteraceae). It comprises 117 species, most of which are annual herbs. Bayesian and parsimony phylogenetic analyses were performed on 51 Emilia species along with closely related genera in the Senecioneae using nuclear ITS and plastid trnL‐trnF sequence data to address questions around the generic circumscription of Emilia, including the status of the similar genera Emiliella and Bafutia, assess Jeffrey's sectional classification of Emilia, and evaluate the distinctness of the morphologically similar species in the large‐headed Emilia coccinea complex. Both nuclear and plastid phylogenies reveal Emilia to be paraphyletic and polyphyletic, with Bafutia and Emiliella nested within Emilia, and Jeffrey's sectional classification is not supported. The phylogenies provide additional evidence that Emilia coccinea and E. caespitosa should be synonymised, as shown by published phenetic cluster and multivariate analyses. The necessary taxonomic changes are made in this manuscript.