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After an 11-year period of exceptional specimen acquisition, we evaluated the robustness of the Western Australian Herbarium Specimen Database in elucidating patterns of diversity and phytogeographic maps of the Southwest Australian Floristic Region (SWAFR). Using rarefaction strategies to compensate for sample bias and a novel approach to multivariate classification and site ordination, we generated maps of floristic provinces and districts in the SWAFR. A 33% increase in specimen numbers and 10% additional taxa were recorded in the study area (SWAFR and 75 km inland buffer) over the 11 years, although historical biases in collecting patterns tended to persist. Although floristic district concepts were robust, regional and provincial concepts were more equivocal. We therefore opted for broad delineations rather than geographically precise ones. We propose a novel phytogeographic map, adding a new floristic province (Kalbarri), five new districts and other boundary adjustments for and in the SWAFR. The updated SWAFR has 8379 native vascular plant taxa (82% species and 18% subspecies), of which 47% are endemic and 49% have been described since 1970. Biodiversity indices generated from collections data should be used cautiously. In contrast, the new phytogeographic regionalization of the SWAFR is robust at the district level. Despite shortcomings, herbarium collections provide the best information available for broadscale analyses of plant diversity. [ABSTRACT FROM AUTHOR]

New Caledonia is a biodiversity hotspot located in the south-western Pacific, well known for its rich, unique and endangered flora. The island flora has a high level of endemism not only at the species level (75%), but also at the generic and family (three endemic) levels. We review here the taxonomic validity of the c. 100 endemic New Caledonian genera of vascular plants (13%) by using the monophyly criterion based on the available phylogenetic data. As observed in other island floras, some of these genera were recovered nested in larger genera and are consequently likely to lose their rank. After a critical review, we concluded that the New Caledonian plant vascular flora contains between 62 and 91 endemic genera. This large variation in the number of endemic genera is mainly caused by a lack of DNA sequences (eight genera) and limited phylogenetic evidence. This work highlights gaps of knowledge that will have to be addressed to stabilize the taxonomy of the New Caledonian flora. Although this study shows that several genera are not monophyletic, New Caledonia still harbours more endemic genera than any other islands in the Pacific Ocean. Preliminary results indicate that the high level of endemism at higher taxonomic levels could be explained by an accumulation of relictual lineages, rather than adaptive radiations. Hypotheses explaining this phenomenon are provided in this study. [ABSTRACT FROM AUTHOR]

Pseudophoenix ekmanii, P. lediniana and P. vinifera ( Arecaceae) are endemic to Hispaniola. The more wide-ranging P. sargentii also occurs on the island. Population genetic diversity and structure of Pseudophoenix was investigated using ten microsatellite loci. The study focused on populations from Hispaniola, but also included samples from other Caribbean islands. Results showed homozygote excess and high inbreeding coefficients in all populations across all polymorphic loci. Populations were highly differentiated. Results from both Bayesian and neighbour-joining cluster analyses identified groups that were consistent with currently accepted species delimitations. We included the only known population of a possible undescribed taxon from the Dominican Republic. Results from the cluster analyses suggested that this putative taxon is closely related to P. sargentii from the Turks and Caicos Islands. There was no significant correlation between population size and observed heterozygosity. Contrary to what was anticipated, protected areas do not harbour most of the genetic diversity of the genus. The Haitian endemic P. lediniana should have the highest priority for conservation because it is restricted to a single population, it has a small number of individuals and it exhibited reduced levels of genetic diversity. The putative new taxon from the Dominican Republic has similar conservation concerns. Future conservation efforts should aim to maintain population connectivity and increase population size, particularly targeting populations with low genetic diversity. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 176, 469-485. [ABSTRACT FROM AUTHOR]

This paper and this issue attempt to address how, when and why the phenomenal c. 100,000 species of seed plants in tropical America (the Neotropics) arose. It is increasingly clear that an approach focusing on individual major biomes rather than a single aggregate view is useful because of evidence for differing diversification histories among biomes. Phylogenetic evidence suggests that Neotropical-scale diversification patterns are structured more ecologically than geographically, with a key role for phylogenetic niche or biome conservatism. Lower geographical structure reflects the fact that long-distance dispersal, inferred from dated phylogenetic trees, has overcome many supposed dispersal barriers. Overall, high rates of species turnover as inferred from palaeontological and molecular data have been the hallmark of plant evolutionary dynamics in the Neotropics throughout the Cenozoic, with most extant species diversity post-dating the Mid- to Late Miocene, perhaps reflecting the conjunction of both global climatic changes and geological upheavals such as the Neogene uplift of the tropical Andes. Future studies of Neotropical diversification will be facilitated by taxonomically and genetically better sampled phylogenetic analyses, their integration with palaeontological, geological and ecological data, and improved methods to estimate biogeographic history and diversification dynamics at different spatial and temporal scales. Future biome-focused approaches would benefit greatly from better delimitation and mapping of Neotropical biomes. © 2012 The Linnean Society of London [ABSTRACT FROM AUTHOR]

Pseudolaelia is endemic to eastern Brazil, with 12 recognized species occurring primarily in the Atlantic Forest and the cerrado, two of the world's biodiversity hotspots. The aims of this study were to: characterize the geographical distribution patterns, richness, diversity and endemism of Pseudolaelia spp.; compare their distribution with that of Full Protection Conservation Units ( FPCUs) and priority areas for biodiversity conservation in Brazil; and determine the species conservation status, indicating areas important for conservation. The biogeography of Pseudolaelia was analysed using herbarium specimens and natural populations, parsimony analysis and geographic information systems. The conservation status was defined according to the International Union for Conservation of Nature. Half of Pseudolaelia spp. are known from less than five sites, and four are micro-endemic, being known from a single site. Nine species should be considered as endangered as a result of habitat degradation. Four species are protected within FPCUs; micro-endemic species are not found in the priority areas for biodiversity conservation. The region of greatest richness, endemism and diversity encompasses the mountainous area in the north-west and north of Espírito Santo and the border with Minas Gerais, this being the central portion of the Cadeia do Espinhaço ( Minas Gerais), a centre of secondary richness and diversity. © 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, ●●, ●●-●●. [ABSTRACT FROM AUTHOR]

New Caledonia is well known for its rich and unique flora. Many studies have focused on the biogeographical origins of New Caledonian plants but rates of diversification on the island have scarcely been investigated. Here, dated phylogenetic trees from selected published studies were used to evaluate the time and tempo of diversification in New Caledonia. The 12 plant lineages investigated all appear to have colonized the island < 37 Mya, when New Caledonia re-emerged after a period of inundation, and the timing of these arrivals is spread across the second half of the Cenozoic. Diversification rates are not particularly high and are negatively correlated with lineage age. The palms have the fastest diversification rates and also the most recent arrival times. The lineage ages of rainforest plants suggest that this ecosystem has been present for at least 6.9 Myr. The New Caledonian flora is apparently a relatively old community that may have reached a dynamic equilibrium. Colonization by new immigrants has been possible until relatively recently and diversity-dependent processes may still be affecting the diversification rates of the earlier colonizers. Further studies on the diversification of large plant clades with exhaustive sampling should help to clarify this. © 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, 170, 288-298. [ABSTRACT FROM AUTHOR]

The Oceanian plant genus Spiraeanthemum (Cunoniaceae) has a centre of diversity in New Caledonia, where it is represented by seven species. Its diversification was investigated using two low-copy nuclear genes, ncpGS and GapC, and phylogenetic analyses were based on maximum parsimony, maximum likelihood and recombination networks. We detected several cases of gene recombination in both datasets, and these have obscured the history within the genus. For S. ellipticum and S. pubescens, accessions from southern populations on ultramafic soils were genetically distinct from accessions from northern populations on non-ultramafic soils. Given that no obvious morphological characters distinguish northern and southern populations in either taxon, both may be considered as examples of cryptic species. Incongruence between gene trees and species' delimitation may be explained by the parallel evolution of similar morphology, differential lineage sorting leading to differential fixation of alleles or different introgression patterns in the north and south leading to allele displacement. In New Caledonia, some species with broad ecological preferences may thus be artificial concepts. This suggests that they should be treated more critically in monographs and that the species' richness of the New Caledonian flora may be underestimated. Problems associated with the typification of S. ellipticum and evidence of hybridization events in the history of Spiraeanthemum are also discussed. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 161, 137–152. [ABSTRACT FROM AUTHOR]

Jacquemontia reclinata House (Convolvulaceae) is a federally listed endangered species endemic to coastal strand habitat of south-eastern Florida. In order to identify the closest relatives of J. reclinata, a phylogenetic reconstruction was performed based on nucleotide sequence data from the internal transcribed spacer region of nuclear ribosomal DNA and from the trnH-psbA intergenic spacer of chloroplast DNA. The three putative relatives of J. reclinata and the majority of Jacquemontia Choicy species known to occur in the Caribbean Islands were included. The strict consensus tree concurs with previous morphological studies, indicating that J. reclinata is closely related to the Caribbean species J. cayensis Britton, J. curtisii Hallier f., and J. havanensis (Jacq.) Urb. These three species and J. reclinata form an unresolved clade. Nucleotide divergence within this clade is low, suggesting that the group is recent, perhaps diversifying after the latest glacial period. These taxa need to be studied further using population-level DNA markers. Most species endemic to the Caribbean Basin form a strongly supported clade. Our phylogeny supports Convolvulus nodiflorus Desr. as part of Jacquemontia. In addition, J. ovalifolia (West) Hallier f. ssp. sandwicensis (A. Gray) K.R. Robertson is sister to the Antillean endemic J. solanifolia (L.) Hallier f. © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society, 2007, 154, 443–454. [ABSTRACT FROM AUTHOR]