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Premise: Understanding evolutionary history and classifying discrete units of organisms remain overwhelming tasks, and lags in this workload concomitantly impede an accurate documentation of biodiversity and conservation management. Rapid advances and improved accessibility of sensitive high-throughput sequencing tools are fortunately quickening the resolution of morphological complexes and   thereby improving the estimation of species diversity. The recently described and critically endangered Banksia vincentia is morphologically similar to the hairpin banksia complex (B. spinulosa s.l.), a group of eastern Australian flowering shrubs whose continuum of morphological diversity has been responsible for taxonomic controversy and possibly questionable conservation initiatives., Methods: To assist conservation while testing the current taxonomy of this group, we used high-throughput sequencing to infer a population-scale evolutionary scenario for a sample set that is comprehensive in its representation of morphological diversity and a 2500-km distribution., Results: Banksia spinulosa s.l. represents two clades, each with an internal genetic structure shaped through historical separation by biogeographic barriers. This structure conflicts with the existing taxonomy for the group. Corroboration between phylogeny and population statistics aligns with the hypothesis that B. collina, B. neoanglica, and B. vincentia should not be classified as species., Conclusions: The pattern here supports how morphological diversity can be indicative of a locally expressed suite of traits rather than relationship. Oversplitting in the hairpin banksias is atypical since genomic analyses often reveal that species diversity is underestimated. However, we show that erring on overestimation can yield negative consequences, such as the disproportionate prioritization of a geographically anomalous population., (© 2022 State of New South Wales. American Journal of Botany published by Wiley Periodicals LLC on behalf of Botanical Society of America.)

The frequency of evolutionary biome shifts during diversification has important implications for our ability to explain geographic patterns of plant diversity. Recent studies present several examples of biome shifts, but whether frequencies of biome shifts closely reflect geographic proximity or environmental similarity of biomes remains poorly known. We explore this question by using phylogenomic methods to estimate the phylogeny of Hakea, a diverse Australian genus occupying a wide range of biomes. Model-based estimation of ancestral regions indicates that Hakea began diversifying in the Mediterranean biome of southern Australia in the Middle Eocene-Early Oligocene, and dispersed repeatedly into other biomes across the continent. We infer around 47 shifts between biomes. Frequencies of shifts between pairs of biomes are usually similar to those expected from their geographic connectedness or climatic similarity, but in some cases are substantially higher or lower than expected, perhaps reflecting how readily key physiological traits can be modified to adapt lineages to new environments. The history of frequent biome-shifting is reflected in the structure of present-day assemblages, which tend to be more phylogenetically diverse than null-model expectations. The case of Hakea demonstrates that the radiation of large plant clades across wide geographic areas need not be constrained by dispersal limitation or conserved adaptations to particular environments., (© 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.)

Background and Aims: The basal eudicot family Proteaceae (approx. 1700 species) shows considerable variation in floral symmetry but has received little attention in studies of evolutionary development at the genetic level. A framework for understanding the shifts in floral symmetry in Proteaceae is provided by reconstructing ancestral states on an upated phylogeny of the family, and homologues of CYCLOIDEA (CYC), a key gene for the control of floral symmetry in both monocots and eudicots, are characterized., Methods: Perianth symmetry transitions were reconstructed on a new species-level tree using parsimony and maximum likelihood. CYC-like genes in 35 species (31 genera) of Proteaceae were sequenced and their phylogeny was reconstructed. Shifts in selection pressure following gene duplication were investigated using nested branch-site models of sequence evolution. Expression patterns of CYC homologues were characterized in three species of Grevillea with different types of floral symmetry., Key Results: Zygomorphy has evolved 10-18 times independently in Proteaceae from actinomorphic ancestors, with at least four reversals to actinomorphy. A single duplication of CYC-like genes occurred prior to the diversification of Proteaceae, with putative loss or divergence of the ProtCYC1 paralogue in more than half of the species sampled. No shifts in selection pressure were detected in the branches subtending the two ProtCYC paralogues. However, the amino acid sequence preceding the TCP domain is strongly divergent in Grevillea ProtCYC1 compared with other species. ProtCYC genes were expressed in developing flowers of both actinomorphic and zygomorphic Grevillea species, with late asymmetric expression in the perianth of the latter., Conclusion: Proteaceae is a remarkable family in terms of the number of transitions in floral symmetry. Furthermore, although CYC-like genes in Grevillea have unusual sequence characteristics, they display patterns of expression that make them good candidates for playing a role in the establishment of floral symmetry., (© The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Premise of the Study: Subtribe Hakeinae (526 spp.) represents a large Australian plant radiation central to our understanding of that flora's evolution and ecology. It contains Grevillea-the third largest plant genus in Australia and a group inferred to have among the highest diversification rates in the angiosperms. However, we lack a robust phylogenetic framework for understanding subtribe Hakeinae and recognize that Grevillea lacks an unambiguous synapomorphy supporting its monophyly., Methods: We used four plastid and one nuclear DNA region from a taxonomically even sampling of a third of the species to infer a time-calibrated phylogeny of Hakeinae and absolute diversification rates of major clades. We developed the R package addTaxa to add unsampled taxa to the tree for diversification rate inference., Key Results: Grevillea is paraphyletic with respect to Hakea and Finschia. Under most parameter combinations, Hakea contains the major clade with the highest diversification rate in Hakeinae, rather than Grevillea. The crown age of the Grevillea+Hakea+Finschia crown group is about double that of prior estimates., Conclusions: We demonstrate that the paraphyly of Grevillea considerably enlarges the number of Australian descendants from its most recent common ancestor but has also misled investigators who considered a single operational taxonomic unit as adequate to represent the genus for inferences of diversification rate and timing. Our time-calibrated phylogeny can form the basis of future evolutionary, comparative ecology, and biogeography studies involving this large Australian plant radiation, as well as nomenclatural changes., (© 2015 Botanical Society of America.)

Background and Aims: When species cohesion is maintained despite ongoing natural hybridization, many questions are raised about the evolutionary processes operating in the species complex. This study examined the extensive natural hybridization between the Australian native shrubs Lomatia myricoides and L. silaifolia (Proteaceae). These species exhibit striking differences in morphology and ecological preferences, exceeding those found in most studies of hybridization to date., Methods: Nuclear microsatellite markers (nSSRs), genotyping methods and morphometric analyses were used to uncover patterns of hybridization and the role of gene flow in morphological differentiation between sympatric species., Key Results: The complexity of hybridization patterns differed markedly between sites, however, signals of introgression were present at all sites. One site provided evidence of a large hybrid swarm and the likely presence of multiple hybrid generations and backcrosses, another site a handful of early generational hybrids and a third site only traces of admixture from a past hybridization event. The presence of cryptic hybrids and a pattern of morphological bimodality amongst hybrids often disguised the extent of underlying genetic admixture., Conclusions: Distinct parental habitats and phenotypes are expected to form barriers that contribute to the rapid reversion of hybrid populations to their parental character state, due to limited opportunities for hybrid/intermediate advantage. Furthermore, strong genomic filters may facilitate continued gene flow between species without the danger of assimilation. Stochastic fire events facilitate temporal phenological isolation between species and may partly explain the bi-directional and site-specific patterns of hybridization observed. Furthermore, the findings suggest that F1 hybrids are rare, and backcrosses may occur rapidly following these initial hybridization events.

Molecular systematics has revolutionized our understanding of the evolution of the Proteaceae. Phylogenetic relationships have been reconstructed down to generic level and below from alignments of chloroplast and nuclear DNA sequences. These trees have enabled the monophyly of all subfamilies, tribes, and subtribes to be rigorously tested and the construction of a new classification of the family at these ranks. Molecular data have also played a major part in testing the monophyly of genera and infrageneric taxa, some of which have been recircumscribed as a result. Molecular trees and chronograms have been used to test numerous previously postulated biogeographic and evolutionary hypotheses, some of which have been modified or abandoned as a result. Hypotheses that have been supported by molecular phylogenetic trees and chronograms include the following: that the proteaceous pattern of repeated disjunct distributions across the southern hemisphere is partly the result of long-distance dispersal; that high proteaceous diversity in south-western Australia and the Cape Floristic Region of South Africa is due to high diversification rates in some clades but is not an evolutionary response to Mediterranean climates; that the sclerophyllous leaves of many shrubby members of the family are not adaptations to dry environments but for protecting mesophyll in brightly illuminated habitats; that deeply encrypted foliar stomata are adaptations for minimizing water loss in dry environments; and that Protea originated in the Cape Floristic Region of South Africa and that one of its subclades has greatly expanded its distribution into tropical savannas. Reconstructing phylogeny down to species level is now the main goal of molecular systematists of the Proteaceae. The biggest challenge in achieving this task will be resolving species trees from numerous gene trees in complexes of closely related species.

Premise of Study: The mechanisms by which plants tolerate water deficit are only just becoming clear. One key factor in drought tolerance is the ability to maintain the capacity to conduct water through the leaves in conditions of water stress. Recent work has shown that a simple feature of the leaf xylem cells, the cube of the thickness of cell walls divided by the lumen width (t/b)(3), is strongly correlated with this ability., Methods: Using ecologically, phylogenetically, and anatomically diverse members of Proteaceae, we tested the relationships between (t/b)(3) and climate, leaf mass per unit area, leaf area, and vein density. To test relationships at high phylogenetic levels (mostly genus), we used phylogenetic and nonphylogenetic single and multiple regressions based on data from 50 species. We also used 14 within-genus species pairs to test for relationships at lower phylogenetic levels., Key Results: All analyses revealed that climate, especially mean annual precipitation, was the best predictor of (t/b)(3). The variation in (t/b)(3) was driven by variation in both lumen diameter and wall thickness, implying active control of these dimensions. Total vein density was weakly related to (t/b)(3) but unrelated to either leaf area or climate., Conclusions: We conclude that xylem reinforcement is a fundamental adaptation for water stress tolerance and, among evergreen woody plants, drives a strong association between rainfall and xylem anatomy. The strong association between (t/b)(3) and climate cannot be explained by autocorrelation with other aspects of leaf form and anatomy that vary along precipitation gradients.

Premise of the Study: The glacial cycles of the Quaternary did not impact Australia in the same way as Europe and North America. Here we investigate the history of population isolation, species differentiation, and hybridization in the southeastern Australian landscape, using five species of Lomatia (Proteaceae). We use a chloroplast DNA phylogeography to assess chloroplast haplotype (chlorotype) sharing among these species and whether species with shared distributions have been affected by shared biogeographic barriers. •, Methods: We used six chloroplast DNA simple sequence repeats (cpSSR) across five species of Lomatia, sampled across their entire distributional range in southeastern Australia. Resulting size data were combined, presented as a network, and visualized on a map. Biogeographical barriers were tested using AMOVA. To explore hypotheses of chlorotype origin, we converted the network into a cladogram and reconciled with all possible species trees using parsimony-based tree mapping. •, Key Results: Some chlorotypes were shared across multiple species of Lomatia in the study, including between morphologically differentiated species. Chlorotypes were either widespread in distribution or geographically restricted to specific regions. Biogeographical structure was identified across the range of Lomatia. The most parsimonious reconciled tree incorporated horizontal transfer of chlorotypes. •, Conclusions: Lomatia shows evidence of both incomplete lineage sorting and extensive hybridization between co-occurring species. Although the species in the study appear to have responded to a number of biogeographic barriers to varying degrees, our findings identified the Hunter River Valley as the most important long-term biogeographic barrier for the genus in southeastern Australia.

Background: Four of the five species of Telopea (Proteaceae) are distributed in a latitudinal replacement pattern on the south-eastern Australian mainland. In similar circumstances, a simple allopatric speciation model that identifies the origins of genetic isolation within temporal geographic separation is considered as the default model. However, secondary contact between differentiated lineages can result in similar distributional patterns to those arising from a process of parapatric speciation (where gene flow between lineages remains uninterrupted during differentiation). Our aim was to use the characteristic distributional patterns in Telopea to test whether it reflected the evolutionary models of allopatric or parapatric speciation. Using a combination of genetic evidence and environmental niche modelling, we focused on three main questions: do currently described geographic borders coincide with genetic and environmental boundaries; are there hybrid zones in areas of secondary contact between closely related species; did species distributions contract during the last glacial maximum resulting in distributional gaps even where overlap and hybridisation currently occur?, Results: Total genomic DNA was extracted from 619 individuals sampled from 36 populations representing the four species. Seven nuclear microsatellites (nSSR) and six chloroplast microsatellites (cpSSR) were amplified across all populations. Genetic structure and the signature of admixture in overlap zones was described using the Bayesian clustering methods implemented in STUCTURE and NewHybrids respectively. Relationships between chlorotypes were reconstructed as a median-joining network. Environmental niche models were produced for all species using environmental parameters from both the present day and the last glacial maximum (LGM).The nSSR loci amplified a total of 154 alleles, while data for the cpSSR loci produced a network of six chlorotypes. STRUCTURE revealed an optimum number of five clusters corresponding to the four recognised species with the additional division of T. speciosissima into populations north and south of the Shoalhaven River valley. Unexpectedly, the northern disjunct population of T. oreades grouped with T. mongaensis and was identified as a hybrid swarm by the Bayesian assignment test implemented in NewHybrids. Present day and LGM environmental niche models differed dramatically, suggesting that distributions of all species had repeatedly expanded and contracted in response to Pleistocene climatic oscillations and confirming strongly marked historical distributional gaps among taxes., Conclusions: Genetic structure and bio-climatic modeling results are more consistent with a history of allopatric speciation followed by repeated episodes of secondary contact and localised hybridisation, rather than with parapatric speciation. This study on Telopea shows that the evidence for temporal exclusion of gene flow can be found even outside obvious geographical contexts, and that it is possible to make significant progress towards excluding parapatric speciation as a contributing evolutionary process.

Premise of the Study: A past study based on morphological data alone showed that the means by which plants of the Australian genus Hakea reduce florivory is related to the evolution of bird pollination. For example, bird pollination was shown to have arisen only in insect-pollinated lineages that already produced greater amounts of floral cyanide, a feature that reduces florivory. We examine a central conclusion of that study, and a common assumption in the literature, that bird pollination arose in insect-pollinated lineages, rather than the reverse., Methods: We combined morphological and DNA data to infer the phylogeny and age of the Australian genus Hakea, using 9.2 kilobases of plastid and nuclear DNA and 46 morphological characters from a taxonomically even sampling of 55 of the 149 species., Key Results: Hakea is rooted confidently in a position that has not been suggested before. The phylogeny implies that bird pollination is primitive in Hakea and that multiple shifts to insect pollination have occurred. The unexpectedly young age of Hakea (a crown age of ca. 10 Ma) makes it coincident with its primary bird pollinators (honeyeaters) throughout its history., Conclusions: Our study demonstrates that Hakea is an exception to the more commonly described shift from insect to bird pollination. However, we note that only one previous phylogenetic study involved Australian plants and their honeyeater pollinators and that our finding might prove to be more common on that continent.

Background: Inter-population distance and differences in breeding times are barriers to reproduction that can contribute to genotypic differentiation between populations. Temporal changes in environmental conditions and local selective processes can further contribute to the establishment of reproductive barriers. Telopea speciosissima (Proteaceae) is an excellent subject for studying the effect of geographic, edaphic and phenological heterogeneity on genotypic differentiation because previous studies show that these factors are correlated with morphological variation. Molecular, morphological and environmental datasets were combined to characterise the relative influence of these factors on inter-population differentiation, and Bayesian analyses were used to investigate current levels of admixture between differentiated genomes., Results: A landscape genetic approach involving molecular and morphological analyses identified three endpoints of differentiated population groups: coastal, upland and southern. The southern populations, isolated from the other populations by an edaphic barrier, show low migration and no evidence of admixture with other populations. Amongst the northern populations, coastal and upland populations are connected along a skewed altitudinal gradient by genetically intermediate populations. The strong association between temperature and flowering time in Telopea speciosissima was shown to maintain a temporally unstable reproductive barrier between coastal and upland populations., Conclusions: Substrate-mediated allopatry appears to be responsible for long-term genetic isolation of the southern populations. However, the temperature-dependent reproductive barrier between upland and coastal populations bears the genetic signature of temporal adjustments. The extreme climatic events of the last glacial maximum are likely to have caused more complete allochronic isolation between upland and coastal populations, as well as exerting increased selective pressure upon local genomes. However, at intermediate altitudes, current climatic conditions allow for the incorporation of alleles from previously distinct genomes, generating new, intermediate genomic assemblages and possibly increasing overall adaptive potential.

Proteaceae subfamily Persoonioideae, as presently circumscribed, consists of the monogeneric tribe Placospermeae (Placospermum) and the tribe Persoonieae. The latter comprises the diverse genus Persoonia and monospecific genera found in New Zealand (Toronia), New Caledonia (Garnieria) and south-western Western Australia (Acidonia). Persoonia has 101 species distributed across Australia and has been classified into 11 informal groups. Using data derived from plastid DNA (trnL--trnF region), nuclear rDNA (ITS) and morphological characters, we constructed a phylogeny of Persoonioideae and compared the results to the existing classification. Bayesian and parsimony analyses indicated that Persoonia, as currently defined, is non-monophyletic. The molecular data and combined molecular and morphological data place Toronia in a moderately well supported clade with the monophyletic Rufiflora group of Persoonia from Western Australia. This clade is sister to Acidonia, Garnieria and the remaining Persoonia species. Of the other informal groups in Persoonia, the Teretifolia, Quinquenervis, Laurina, Arborea, Graminea and Chapmaniana groups are supported as monophyletic. The Lanceolata group can be re-circumscribed to be monophyletic by the addition of P. elliptica R.Br. (Longifolia group) and the Dillwynioides group. Relationships within this large, geographically widespread clade are largely unresolved and low DNA-sequence variation within it suggests a recent radiation followed by isolation in south-western and eastern Australia. All endemic Tasmanian Persoonia (Gunnii group taxa) are unresolved at the secondmost basal node of the Persoonieae. Our results suggest that the Rufiflora group should be treated as a new genus and that the infrageneric taxonomy of Persoonia requires minor amendment. [ABSTRACT FROM AUTHOR]

Aim Ecologically driven diversification can create spectacular diversity in both species numbers and form. However, the prediction that the match between intrinsic (e.g. functional trait) and extrinsic (e.g. climatic niche) variables may lead to evolutionary radiation has not been critically tested. Here, we test this hypothesis in the Southern Hemisphere plant family Proteaceae, which shows a spectacular diversity in open mediterranean shrublands in the Southwest Australian Floristic Region (SWAFR) and the Cape Floristic Region (CFR). Species in the Proteaceae family occupy habitats ranging from tropical rain forests to deserts and are remarkably variable in leaf morphology. Location Southern Hemisphere. Methods We built a phylogenetic tree for 337 Proteaceae species (21% of the total), representing all main clades, climatic tolerances and morphologies, and collected leaf functional traits (leaf area, sclerophylly, leaf shape) for 261 species and climatic niche data for 1645 species. Phylogenetic generalized least squares regression and quantitative-trait evolutionary model testing were used to investigate the evolutionary pathways of traits and climatic niches, and their effect on diversification rates. Results We found that divergent selection may have caused lineages in open vegetation types to evolve towards trait and climatic niche optima distinct from those in closed forests. Furthermore, we show that the interaction between open habitats, dry, warm and/or mediterranean climates, and small, sclerophyllous, toothed leaves increases net diversification rates in Proteaceae. Main conclusions Our results suggest that the evolution of specific leaf adaptations may have allowed Proteaceae to adapt to variable climatic niches and diversify extensively in open ecosystems such as those in the CFR and SWAFR. This match between morphology and environment may therefore more generally lead to evolutionary radiation. [ABSTRACT FROM AUTHOR]

Specimens of all known taxa and putative entities belonging to the Banksia spinulosa complex were collected from Kuranda in northern Queensland, western to central Queensland and down the eastern coast of Australia to Wilsons Promontory in southern Victoria. These specimens were used to investigate morphological variation in habit, stems, leaves, inflorescences, fruits and seeds in the complex. Phenetic analysis (unweighted pair-group method with arithmetic mean, UPGMA, clustering and semi-strong hybrid multi-dimensional scaling, SSH–MDS, ordination) was performed on the full dataset of 233 entities using 33 characters (18 quantitative, two binary and 13 multistate). To facilitate visualisation of patterns in both clustering and ordination, we also analysed subgroups based on the results of the phenogram from the full dataset. The results showed that the five known and described taxa are phenetically distinct, viz. B. collina sens. str., B. cunninghamii sens. str., B. neoanglica, B. spinulosa and B. vincentia, and provided support for a further 12 morphometrically diagnosable entities, four of which could not be diagnosed with simple combinations of character states and require further investigation. The present study has highlighted that there is much more hidden morphological diversity in the B. spinulosa complex than has previously been recognised in any of the current competing taxonomies. [ABSTRACT FROM AUTHOR]

Lomatia R.Br. is a genus of 12 species in South America and eastern Australia. Hybridisation is extensive in the Australian species and molecular work is required to understand phylogenetic relationships and examine potential gene flow among species. We developed a library of microsatellite markers for Lomatia silaifolia (Sm.) R.Br. These markers were tested across population samples of L. silaifolia and L. myricoides (C.F.Gaertn.) Domin, assessed for cross amplification across all 12 species of Lomatia, sequenced and inspected for variation in the microsatellite flanking region (MFR), and utilised for phylogeographic and phylogenetic analysis. Nineteen microsatellite markers were tested, 13 of which were polymorphic in size analysis. Four of the markers amplified consistently within Lomatia and the MFR had equivalent to or more sequence variation than the three universal markers (psbA-trnH intergenic spacer, PHYA, ITS). Variation within five individuals of L. silaifolia indicated that MFR could be phylogeographically informative. Combined phylogenetic analysis of Lomatia using universal markers andMFRresulted in a well supported tree; however, phylogenetic analysis of only MFR suggested non-monophyly of the species. Phylogenetic trees supported South American species as being diverged from the Australian species but paraphyletic with respect to the Australian lineage. Relationships among Australian species of Lomatia are correlated with geography rather than morphology. We found that microsatellite markers designed for Lomatia and the flanking regions can be informative at population, phylogenetic and phylogeographic levels. [ABSTRACT FROM AUTHOR]

Abstract: The angiosperm family Proteaceae is a distinct component of the Cape Floristic Region biodiversity hotspot with 330 endemic species. Phylogenetic analyses of subfamily Proteoideae using sequence data from one nuclear and six plastid loci show that most of this diversity is contained in two distinct Cape floral clades. Molecular dating analyses, using Bayesian and penalized likelihood methods and four phylogenetically supported fossil age constraints, reveal contrasting histories for these two clades. The genus Protea belongs to a lineage that may have been in Africa since the Late Cretaceous but began to diversify in the Cape only 5–18Myr ago. In contrast, the Leucadendrinae clade presumably arrived in the region no earlier than 46Myr ago by long-distance dispersal from an Australian ancestor and the extant members of this clade began to diversify in the Cape 22–39Myr ago. These results join a growing number of case studies that challenge the commonly accepted view that most of the Cape flora radiated synchronously in the Late Miocene and Early Pliocene when a Mediterranean climate settled in the region. [Copyright &y& Elsevier]

Tribe Macadamieae (91 spp., 16 genera; Proteaceae) is widespread across the southern hemisphere on all major fragments of Gondwana except New Zealand and India. Macadamia is cultivated outside its natural range as a "nut" crop (notably in Hawaii, where it is the principal orchard crop). We sampled seven DNA regions and 53 morphological characters from the tribe to infer its phylogeny and address the common assumption that the distribution of the extant diversity of the tribe arose by the rafting of ancestors on Gondwanan fragments. Macadamia proves to be paraphyletic with respect to the African genus Brabejum, the South American genus Panopsis, and the Australian species Orites megacarpus. We erect two new generic names, Nothorites and Lasjia, to produce monophyly at that rank. The earliest disjunctions in the tribe are inferred to be the result of long-distance dispersal out of Australia (with one possible exception), rather than vicariance. Evolution of tardy fruit dehiscence is correlated with these dispersals, and the onset of the Antarctic Circumpolar Current (ACC) precedes them. We suggest that the ancestors of extant diversity arrived on their respective continents via the ACC, and we recognize that this is a mechanism precluded, rather than facilitated,by Gondwana's terrestrial continuity. [ABSTRACT FROM AUTHOR]

Sunken, covered, and encrypted stomata have been anecdotally linked with dry climates and reduced transpiration and therefore have been used to infer dry palaeoclimates from fossils. This study assesses the evolutionary and ecological associations of such stomatal protection in a model system-the diverse southern hemisphere family Proteaceae. Analyses were based on the morphology of over 1400 Australian, South African, New Caledonian, New Zealand, and South American species, anatomy of over 300 of these species, and bioclimatic data from all 1109 Australian species. Ancestral state reconstruction revealed that five or six evolutionary transitions explain over 98% of the dry climate species in the family, with a few other, minor invasions of dry climates. Deep encryption, i.e., stomata in deep pits, in grooves, enclosed by tightly revolute margins or strongly overarched by cuticle, evolved at least II times in very dry environments. Other forms of stomatal protection (sunken but not closely encrypted stomata, papi!lae, and layers of hairs covering the stomata) also evolved repeatedly, but had no systematic association with dry climates. These data are evidence for a strong distinction in function, with deep encryption being an adaptation to aridity, whereas broad pits and covered stomata have more complex relations to climate. [ABSTRACT FROM AUTHOR]

Abstract: In plants, understanding the interactions between breeding systems and pollination ecology may enable us to predict the impacts of rarity. We used a comparative approach to test whether rarity is associated with reproductive biology in two closely-related species pairs. This system has been recently altered by changes in fire regimes and the introduction of European honeybees. More than 35% of flowers matured fruits in the common species after natural-pollination compared to <20% of flowers in the rare species. All species were obligate outcrossers in each of the study populations, but only the two rare species were pollen-limited, having significantly lower fruit-set on open-pollinated flowers than those cross-pollinated by hand (mean±SE; 0.18±0.02 vs. 0.42±0.05; p <0.001). Native bees (Leioproctus species) and introduced honeybees (Apis mellifera) visited all species. The native bees visited fewer flowers within a plant and moved greater distances between plants while foraging than honeybees, so the native bees are expected to be more effective in promoting outcrossing. While honeybees were the most frequent visitors to flowers of all species, native bees made more visits to common than rare species (0.65±0.20 vs. 0.20±0.09). Our results suggest that the poorer reproductive success in rare Persoonia species is associated with lower pollinator effectiveness, which is exacerbated by frequent fires and introduced honeybees. If this is a causal relationship, this may increase the probability of extinction in populations of these species. [Copyright &y& Elsevier]