Michael J. Bayly

Classification, Origin, and Diversification of the New Zealand Hebes (Scrophulariaceae)

The New Zealand hebes (Scrophulariaceae) are members of a large Southern Hemisphere clade nested within Veronica. Analysis of ITS and rbcL sequences suggests that the New Zealand species are derived from a single common ancestor that arrived via long-distance dispersal. After the establishment of this initial founder population in New Zealand, the hebes have undergone at least two major episodes of diversification, giving rise to six clades. The great degree of morphological diversity in the New Zealand hebes contrasts with a corresponding low level of sequence divergence. New Zealand was a source of new emigrants to other regions in the South Pacific that were preadapted to high mountains or forest margins. Our results suggest that two instances of long-distance dispersal from New Zealand to South America, at least one instance from New Zealand to Australia, and one instance from New Zealand to New Guinea have occurred relatively recently. Shorter hops to the Chatham Islands and the subantarctic islands are also supported by the sequence data.

ETS sequences support the monophyly of the eucalypt genus Corymbia (Myrtaceae)

The generic classification of the eucalypts, especially recognition of the genus Corymbia, has been controversial. The phylogeny of Corymbia and related eucalypt groups was investigated using nuclear ETS sequences, and combined ETS and ITS sequences. Both the ETS and combined datasets support the monophyly of Corymbia. Three major eucalypt clades are confirmed: Corymbia + Angophora; Eucalyptus s.s.; and the Eucalyptopsis group. Within Corymbia, relationships are broadly consistent with phylogenies based on morphological and anatomical characters; sections Ochraria, Blakearia, and Politaria are all supported as monophyletic; sect. Rufaria is monophyletic with the inclusion of the monotypic sect. Apteria. Within Eucalyptus s.s., relationships are generally consistent with those shown by previous molecular studies. Within the Eucalyptopsis group, Allosyncarpia is sister to the clade Stockwellia + Eucalyptopsis. Relationships between the major eucalypt clades are equivocal, but combined analysis of ETS and ITS data shows Corymbia + Angophora as sister to Eucalyptus-the rainforest taxa of the Eucalyptopsis group being outside this clade. Patterns of relationship and distribution are consistent with differentiation of major lineages of Corymbia prior to the isolation of taxa (now relictual) in eastern and south-western Australia, arguably before the midMiocene.

Phylogeny, major clades and infrageneric classification of Corymbia (Myrtaceae), based on nuclear ribosomal DNA and morphology

Phylogenetic relationships of sections and species within Corymbia (Myrtaceae), the bloodwood eucalypts, were evaluated by using combined analyses of nuclear rDNA (ETS + ITS) and morphological characters. Combining morphological characters with molecular data provided resolution of relationships within Corymbia. The analyses supported the monophyly of the genus and recognition of the following two major clades, treated here as new subgenera: subgenus Corymbia, including informal sections recognised by Hill and Johnson (1995), namely Rufaria (red bloodwoods), Apteria and Fundoria; and subgenus Blakella, including sections Politaria (spotted gums), Cadagaria, Blakearia (paper-fruited bloodwoods or ghost gums) and Ochraria (yellow bloodwoods). Hill and Johnson’s section Rufaria is monophyletic if Apteria and Fundoria are included. It is evident that, among the red bloodwoods, series are not monophyletic and several morphological characters result from convergent evolution. There was strong morphological and molecular evidence that the three species of red bloodwoods that occur in south-western Western Australia (series Gummiferae: C. calophylla and C. haematoxylon, and series Ficifoliae: C. ficifolia) form a monophyletic group, separate from the eastern C. gummifera (series Gummiferae), which is probably sister to the clade of all other red bloodwoods. Phylogenetic results supported recognition of new taxonomic categories within Corymbia, and these are formalised here.

Phylogeographic patterns in the Australasian genus Chionohebe (Veronica s.l., Plantaginaceae) based on AFLP and chloroplast DNA sequences

The alpine genus Chionohebe is one of seven genera in the southern hemisphere Hebe complex. The main aims of this study were to infer the evolutionary relationships and assess phylogeographic patterns among the six species of Chionohebe, determine the origin of the two species with trans-Tasman distributions, and test species delimitations and specimen identifications based on morphology. Analyses of AFLP data recovered five major lineages within Chionohebe, some of which corresponded to species and varieties as currently circumscribed. Although the cushion chionohebes were strongly supported as monophyletic, the sole non-cushion species, C. densifolia, was sister to Parahebe trifida, and thus the AFLP data do not support a monophyletic Chionohebe as usually circumscribed. Strong north/south and west/east phylogeographic patterns were found among and within the main AFLP lineages in New Zealand. Analyses of chloroplast DNA (cpDNA) revealed eight haplotypes in Chionohebe, but these did not correspond to current taxonomy or geography due to widespread interspecific haplotype sharing. Based on both AFLP and cpDNA results, the two trans-Tasman species are shown to have originated in New Zealand and dispersed to Australia independently.

Historical biogeographical patterns in continental Australia: congruence among areas of endemism of two major clades of eucalypts

Published phylogenies of two eucalypt clades, red bloodwoods Corymbia subgenus Corymbia and eudesmids Eucalyptus subgenus Eudesmia (Myrtaceae), were combined for an analysis of historical biogeographical area relationships within continental Australia. The method of paralogy‐free subtree analysis was used to eliminate geographical paralogy; the paralogy‐free subtrees were coded as characters for parsimony analysis to find the minimal and area cladogram, which proved to be informative of a continent‐wide pattern. The eucalypt fossil record and molecular dating studies allow an interpretation of the biogeographical history in terms of major vicariance events that date from the early Paleogene. The summary area cladogram shows the wet jarrah forest region of South‐West Western Australia, a region of high endemism, as the earliest to differentiate from all other areas, isolated by marine inundation across southern Australia and climatic cooling in the Late Eocene–Early Oligocene. From about this time, regionalization continued, with warmer conditions and monsoonal climate developing in central and northern Australia, and cooling in the south‐east. Northern and eastern humid and semi‐humid areas were related as a track, but with increased aridity in the interior of the continent, the monsoonal climate contracted northwards. The Australian Monsoon Tropics (AMT: Kimberley, Top End, Arnhem, Cape York and inland north‐east Queensland) differentiated from eastern areas (Queensland wet tropics to McPherson–Macleay). Our results also show all arid and semi‐arid regions as related, suggestive of a historically cohesive interior biota rather than repeated colonizations of the interior from the periphery of the continent. Climate largely differentiates hot arid areas in the north (Pilbara, Northern and Central deserts) from arid areas in the south (south‐west interzone, Wheatbelt, Goldfields and Great Victoria Desert).

Molecular phylogenetic analysis of Dendrobium (Orchidaceae), with emphasis on the Australian section Dendrocoryne, and implications for generic classification

Sequences of the internal transcribed spacers (ITS) of nuclear rDNA were obtained for a broad range of dendrobium orchids for phylogenetic analysis using parsimony. A progressive approach was used to identify functional outgroups for analysis of all taxa in Dendrobium sect. Dendrocoryne. Our first, broadest analysis confirmed the results of other workers that Dendrobium sensu lato includes a major Australasian clade and a sister Asian clade. In the Australasian clade, the New Zealand species D. cunninghamii (=gen. Winika, Clements et al. 1997) was identified as the sister group to a well supported clade that includes the genera Cadetia, Diplocaulobium and Flickingeria, and Dendrobium sects Grastidium, Latouria, Spatulata, Australorchis (=gen. Australorchis), Rhizobium (= gen. Dockrillia) and Dendrocoryne. Sect. Dendrocoryne is probably polyphyletic, with two species, D. aemulum and D. callitrophilum (=gen. Tropilis), outside the main group and sect. Rhizobium (= gen. Dockrillia) nested within it. Sect. Australorchis (= gen. Australorchis) is possibly the sister group to the clade of Rhizobium plus the main group of Dendrocoryne. Thelychiton (a genus reinstated for several species in Dendrocoryne) is polyphyletic, given that Tetrabaculum (=D. tetragonum complex) and Dockrillia fall within the same clade. The splitting of the Australasian dendrobiums into various genera by other authors is excessive and unnecessary, and alternative taxonomic treatments are offered here for debate. Our study included accessions for all varieties in the following three widespread eastern Australian species: D. speciosum, D. kingianum and D. tetragonum. Each of these species showed significant sequence divergence between particular geographic regions, but some varieties had identical sequences. The splitting of D. speciosum into 11 species is not supported. We identified pseudogenes in the ITS region for D. fleckeri and D. finniganense, which appear to have evolved before these two species diverged, but support their sister relationship. Sequences for D. callitrophilum and D. (Grastidium) baileyi (the latter from GenBank) also appear to be pseudogenes, and these taxa need further study.

Ribosomal DNA pseudogenes are widespread in the eucalypt group (Myrtaceae): implications for phylogenetic analysis

Pseudogenes from the 18S−5.8S−26S cistron of nuclear ribosomal DNA are reported in the eucalypt group (Myrtaceae), which includes seven genera. Putative pseudogenes are identified by a range of sequence comparisons including: the number of CpG and CpNpG methylation sites, GC content, estimated secondary structure stability of internal transcribed spacer transcripts, the presence of conserved motifs, patterns of sequence relationships and inferred substitution patterns. These comparisons indicate that pseudogenes are widespread, being evident in Eucalyptus (subgenera Eucalyptus and Eudesmia), Corymbia (extracodical sections Rufaria, Ochraria and Blakearia), Angophora, Stockwellia quadrifida and Arillastrum gummiferum. At least six sequences used in previous phylogenetic studies are identified as pseudogenes, and a further 10 pseudogenes are newly sequenced here. Gene trees place pseudogenes in a number of distinct lineages: pseudogenes from Eucalyptus group with other Eucalyptus sequences, those from Corymbia and Angophora group with other Corymbia/Angophora sequences, that from Stockwellia groups with other sequences from the Eucalyptopsis group, and that from Arillastrum is placed as sister to the other included sequence of Arillastrum. Some pseudogenes in Eucalyptus, Corymbia and Angophora represent “deep” ribosomal DNA paralogues that pre‐date species differentiation in these groups, and a recombination analysis shows no evidence of recombination between putative pseudogenes and their functional counterparts. The presence of divergent paralogues presents both challenges and opportunities for the reconstruction of eucalypt phylogenies using ribosomal DNA sequences. Phylogenetic data sets should include only orthologous sequences, but different paralogues potentially provide additional, independent, character sets for phylogenetic analyses.

Major clades of Australasian Rutoideae (Rutaceae) based on rbcL and atpB sequences.

Background Rutaceae subfamily Rutoideae (46 genera, c. 660 species) is diverse in both rainforests and sclerophyll vegetation of Australasia. Australia and New Caledonia are centres of endemism with a number of genera and species distributed disjunctly between the two regions. Our aim was to generate a high-level molecular phylogeny for the Australasian Rutoideae and identify major clades as a framework for assessing morphological and biogeographic patterns and taxonomy. Methodology/Principal Findings Phylogenetic analyses were based on chloroplast genes, rbcL and atpB, for 108 samples (78 new here), including 38 of 46 Australasian genera. Results were integrated with those from other molecular studies to produce a supertree for Rutaceae worldwide, including 115 of 154 genera. Australasian clades are poorly matched with existing tribal classifications, and genera Philotheca and Boronia are not monophyletic. Major sclerophyll lineages in Australia belong to two separate clades, each with an early divergence between rainforest and sclerophyll taxa. Dehiscent fruits with seeds ejected at maturity (often associated with myrmecochory) are inferred as ancestral; derived states include woody capsules with winged seeds, samaras, fleshy drupes, and retention and display of seeds in dehisced fruits (the last two states adaptations to bird dispersal, with multiple origins among rainforest genera). Patterns of relationship and levels of sequence divergence in some taxa, mostly species, with bird-dispersed (Acronychia, Sarcomelicope, Halfordia and Melicope) or winged (Flindersia) seeds are consistent with recent long-distance dispersal between Australia and New Caledonia. Other deeper Australian/New Caledonian divergences, some involving ant-dispersed taxa (e.g., Neoschmidia), suggest older vicariance. Conclusions/Significance This comprehensive molecular phylogeny of the Australasian Rutoideae gives a broad overview of the group’s evolutionary and biogeographic history. Deficiencies of infrafamilial classifications of Rutoideae have long been recognised, and our results provide a basis for taxonomic revision and a necessary framework for more focused studies of genera and species.

Shared phylogeographic patterns and widespread chloroplast haplotype sharing in Eucalyptus species with different ecological tolerances

We examined the phylogeography of three south-east Australian trees (Eucalyptus delegatensis, Eucalyptus obliqua, and Eucalyptus regnans) with different tolerances, in terms of cold, drought, fire and soil to explore whether species with different ecologies share major phylogeographic patterns. A second aim of this study was to examine geographic patterns of chloroplast DNA (cpDNA) haplotype sharing among the three study species. Trees of E. delegatensis (n = 120), E. obliqua (n = 265) and E. regnans (n = 270) were genotyped with five cpDNA microsatellite markers. The species shared major phylogeographic disjunctions, and common patterns at proposed glacial refugia (generally high haplotype diversity) and areas thought to have been treeless during the Last Glacial Maximum (LGM) (low diversity). Inter-specific sharing of haplotypes was extensive, and fixation of shared, regional haplotypes was more frequent in areas postulated as having been treeless at the LGM. Despite ecological differences, chloroplast microsatellite data suggest the three species have responded to past climatic changes in a similar way, by persisting in multiple, generally common refugia. We suggest that the natural ability of eucalypt species to hybridise with others with quite different or broader ecological tolerances may provide an “insurance policy” for response to rapidly changing abiotic conditions.

A taxonomic revision of the Hebe parviflora complex (Scrophulariaceae), based on morphology and flavonoid chemistry

Abstract Two entities have long been recognised at the rank of either species or variety in the New Zealand endemic Hebe parviflora complex but, because one of the critical type specimens had not previously been examined by New Zealand botsnists, there has been uncertainty regarding the correct application Of names. The two entities Can be distinguished on characters of habit, leaves, flowers, leaf flavonoids, and chromosome number, and are accepted here at species rank. H. parvlflora is the correct name for the tetraploid entity previously known as H. parvrflora var. arborea, and H. stenophylla is the diploid entity previously known as H. parviflora var. angustifolia (the autonym var. parviflora has not been used in any recent treatments). H. stenophylla has several distinct geographic races and new names are provided at varietal rank for two of these: var. hesperia occurs in limestone areas near the north‐west coast of the South Island, between Cape Farewell and the Heaphy River; var. oliveri occurs on exposed bluffs on Stephens Island in Cook Strait. Circumscription of these varieties leaves var. stenophylla comprising a range of morphological forms whose relationships require further elucidation. A comparative study of leaf flavonoids identifies flavonoid characters that clearly distinguish H. parviflora and H. stenophylla, and the profiles of these species are compared with those of the related species H. strictissima and H. traversii. Historical factors affecting the distribution of H. parviflora and H. stenophylla are discussed, and descriptions, distribution maps, and illustrations of diagnostic morphological characters are provided for all taxa.