Fire is an important ecological disturbance in vegetated ecosystems across the globe, and also has considerable impacts on human infrastructure. Vegetation flammability is a key bottom-up control on fire regimes and on the nature of individual fires. Although New Zealand (NZ) historically had low fire frequencies, anthropogenic fires have considerably impacted indigenous vegetation as humans used fire extensively to clear forests. Few studies of vegetation flammability have been undertaken in NZ and only one has compared the flammability of indigenous plants; this was a qualitative assessment derived from expert opinion. We addressed this knowledge gap by measuring the flammability of terminal shoots from a range of trees and shrubs found in NZ. We quantified shoot flammability of 60 indigenous and exotic species, and compared our experimentally derived ranking with expert opinion. The most flammable species was the invasive exotic shrub Gorse (Ulex europaeus), followed by Manna Gum (Eucalyptus viminalis), Kūmarahou (Pomaderris kumeraho), Rimu (Dacrydium cupressinum) and Silver Beech (Lophozonia menziesii). Our experimentally derived ranking was strongly correlated with expert opinion, lending support to both methods. Our results are useful to ecologists seeking to understand how fires have and will influence NZ’s ecosystems, and for fire managers identifying high-risk landscapes, and low flammability species for ‘green firebreaks’.

Summary: Some plant traits may be legacies of coevolution with extinct megafauna. One example is the convergent evolution of ‘divaricate’ cage architectures in many New Zealand lineages, interpreted as a response to recently extinct flightless avian browsers whose ancestors arrived during the Paleogene period. Although experiments have confirmed that divaricate habit deters extant browsers, its abundance on frosty, droughty sites appears consistent with an earlier interpretation as a response to cold, dry Plio‐Pleistocene climates. We used 45 protein‐coding sequences from plastid genomes to reconstruct the evolutionary history of the divaricate habit in extant New Zealand lineages. Our dated phylogeny of 215 species included 91% of New Zealand eudicot divaricate species. We show that 86% of extant divaricate plants diverged from non‐divaricate sisters within the last 5 Ma, implicating Plio‐Pleistocene climates in the proliferation of cage architectures in New Zealand. Our results, combined with other recent findings, are consistent with the synthetic hypothesis that the browser‐deterrent effect of cage architectures was strongly selected only when Plio‐Pleistocene climatic constraints prevented woody plants from growing quickly out of reach of browsers. This is consistent with the abundance of cage architectures in other regions where plant growth is restricted by aridity or short frost‐free periods.

Pennantia, which comprises four species distributed in Australasia, was the subject of a monographic taxonomic treatment based on morphological characters in 2002. When this genus has been included in molecular phylogenies, it has usually been represented by a single species, P. corymbosa J.R.Forst. & G.Forst., or occasionally also by P. cunninghamii Miers. This study presents the first dated phylogenetic analysis encompassing all species of the genus Pennantia and using chloroplast DNA. The nuclear ribosomal 18S–26S repeat region is also investigated, using a chimeric reference sequence against which reads not mapping to the chloroplast genome were aligned. This mapping of off-target reads proved valuable in exploiting otherwise discarded data, but with rather variable success. The trees based on chloroplast DNA and the nuclear markers are congruent but the relationships among the members of the latter are less strongly supported overall, certainly due to the presence of ambiguous characters in the alignment resulting from low coverage. The dated chloroplast DNA phylogeny suggests that Pennantia has diversified within the last 20 My, with the lineages represented by P. baylisiana (W.R.B.Oliv.) G.T.S.Baylis, P. endlicheri Reissek and P. corymbosa diversifying within the last 9 My. The analyses presented here also confirm previous molecular work based on the nuclear internal transcribed spacer region showing that P. baylisiana and P. endlicheri, which were sometimes considered synonyms, are not sister taxa and therefore support their recognition as distinct species.

Argophyllaceae is a small eudicot family of trees and shrubs of south‐western Pacific distribution, comprising two genera: Corokia and Argophyllum . The phylogeny of Corokia , which contains six species, has attracted little attention so far, the genus being usually represented by a single species in studies looking at relationships at higher taxonomic levels. Here we bridge this knowledge gap with a complete phylogeny of the genus based on whole‐plastid DNA sequences. We also investigated nuclear ribosomal DNA markers, which yielded a poorly supported phylogeny. Comparing fossil‐calibrated and biogeographic dating approaches, we conclude that extant Argophyllaceae species are probably not Gondwanan relicts, the timing of their divergences being better explained by long‐distance dispersal after the break‐up of Gondwana than by vicariance. The high level of endemicity of the species of Corokia prevents the reconstruction of a precise biogeographic history of the genus, but our phylogenies suggest that the genus originated in Australia, then about 3.5 My ago started dispersing eastwards into the Pacific towards its present‐day distribution.

Neomyrtus is a New Zealand endemic monotypic genus that has been assigned to the Myrtaceae tribe Myrteae. Previous phylogenetic studies using the five genetic markers ITS, ETS, mat K, psb A‐ trn H, and rpl 16 have placed the single species Neomyrtus pedunculata in a clade with the New Zealand endemic Lophomyrtus (subtribe Ugninae), comprising the two species L. bullata and L. obcordata . Examination of the single herbarium voucher (OTA 57310) representing the plant material from which the DNA for the five phylogenetic markers was obtained revealed that it had been misidentified as Neomyrtus pedunculata and that it actually belongs to Lophomyrtus obcordata . We conducted a reanalysis of previously published data with new sequences from Neomyrtus and also undertook an analysis of 85 kbp of plastid protein coding genes from available Myrteae plastid genomes. These new phylogenetic analyses place Neomyrtus as sister to the New Caledonian endemic genus Myrtastrum , and the two species of Lophomyrtus form a clade that is sister to the Australian endemic Lenwebbia . Neomyrtus and Lophomyrtus are not closely related within the context of the tribe. This change to the understanding of Myrteae phylogeny is discussed in terms of available morphological character data and the biogeography of the tribe. Myrtastrum is currently treated as incertae sedis at subtribal rank, but along with Neomyrtus could be considered as representing a new subtribe as our analyses suggest they are not part of any of the clades hitherto recognised as subtribes.