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Pteridium (the bracken) is a genus of common and widely distributed ferns throughout the world. The variation patterns of morphology in the genus are highly complex and no consensus has been reached among taxonomists regarding the number of species as well as subdivision of the variable species. To address the question of how many species and subspecies of Pteridium occur in Asia, 75 populations were sampled in Bolivia, China, Japan, Malaysia, Mexico and Peru. Sequence data of three chloroplast DNA regions, rps4-trnSGGA, rpl16 and trnSGCU-trnGUCC and the genotype data of three microsatellite loci were collected. The newly generated sequence data combined with the sequences already available from GenBank for samples from all over the world were subjected to several phylogenetic analyses and species delimitation tests. The results support recognition of two diploid species, P. aquilinum in the Northern Hemisphere and Africa and P. esculentum in South America and Australia. Evidence was found to recognize one Asian tetraploid species, P. semihastatum. The Eurasian occurrences of P. aquilinum can be further subdivided into subsp. aquilinum occurring in Africa, Europe and Asia Minor; subsp. japonicum occurring from East Asia to eastern Europe; subsp. wightianum occurring from central China to Malesia (Malay Peninsula, New Caledonia, New Zealand) and northern Australia. The North American subsp. latiusculum was also found in India. Some local "species" recorded in Flora of China likely represent hybrids between subsp. japonicum and subsp. wightianum. Keywords chloroplast; microsatellite; phylogeny; phylogeography; Pteridium; taxonomy

Biogeography is a multidisciplinary science concerned with how and why organisms are distributed as they are on Earth. It links fields such as systematics, ecology, paleontology, and climatology, and occupies a central position in evolutionary biology, being fundamental to the study of processes such as speciation and adaptive radiation. Here we provide a brief overview of some particularly dynamic areas of inquiry and offer some perspectives on future directions for the field. We hope that some historical debates, such as those over the importance of dispersal, or the validity of molecular dating, are finally being put to rest. Over the last decade, biogeography has become increasingly integrative, and has benefited from advances in statistical methods for inferring geographic range dynamics in a phylogenetic context, molecular estimation of lineage divergence times, and modeling lineage birth and death. These are enabling greater insights into patterns of organismal diversification in time and space. In the next decade, analytical challenges are emerging on several fronts. For example, phylogenies are increasing in size and taxonomic breadth and new sequencing technologies enabling phylogenetic and phylogeographic datasets are increasingly genomic in depth. In addition, geographic occurrence data are accumulating in online repositories, yet tools for data mining and synthetic analysis are lacking for comparative multi-lineage studies. Biogeography is thus entering an era characterized by phylogenomic datasets, increasingly comprehensive sampling of clades, and interdisciplinary synthesis. We anticipate continued progress in our understanding of biodiversity patterns at regional and global scales, but this will likely require greater collaboration with specialists in bioinformatics and computational science. Finally, it is clear that biogeography has an increasingly important role to play in the discovery and conservation of biodiversity. Lessons learned from biogeographic studies of islands are being applied to better understand extinction dynamics as continental ecosystems become more fragmented, and phylogeography and ecological niche modeling offer innovative paths toward the discovery of previously unknown species distributions and priority areas for conservation. The future of biogeography is bright and filled with exciting challenges and opportunities.

Soroseris, Stebbinsia, and Syncalathium are three genera of the sunflower family (Asteraceae) with restricted distributions on high screes of the Tibetan Plateau. We present a molecular analysis to test the monophyly of the genera, evaluate the phylogenetic relationships and construct their biogeographic diversification history. Nuclear ITS and plastid trnL-F and psbA-trnH fragments were analyzed with parsimony, Bayesian inference, and relaxed Bayesian dating for all species of Soroseris, Stebbinsia, and Syncalathium. Stebbinsia is part of a polytomy with several lineages of Soroseris. Syncalathium is biphyletic with Syn. souliei placed within subtribe Lactucinae and the remaining species close to the Soroseris-Stebbinsia clade within subtribe Crepidinae. Bayesian dating based on ITS sequences and using four fossil calibrations suggests that the stem and crown ages of the Soroseris-Stebbinsia clade and the two groups of Syncalathium are between 8.44 and 1.56 million years. Stebbinsia should be treated as a section of Soroseris and Syncalathium souliei should be excluded from Syncalathium and either placed in Lactuca s.l. or established as a new genus in Lactucinae. The remaining species are to be treated as Syncalathium s.str. in Crepidinae. The diversification of these groups in the Tibetan Plateau is of relatively young age, and can be explained by rapid diversification and radiation of the Soroseris-Stebbinsia clade, allopatric speciation within Syncalathium s.str. and convergent evolution of Syncalathium s.str. and Syn. souliei. The speciation events correlated with climatic change and fragmentation of scree habitats during the uplift of the Tibetan Plateau. Possible migration routes in Syncalathium s.str. from the northeast to the central and southern part of the Tibetan Plateau are suggested.

Salix is a taxonomically difficult genus and its generic limits and infrageneric division are still highly controversial. We employed sequences of the chloroplast rbcL gene, trnD-T spacer and atpB-rbcL spacer for phylogenetic analyses of Salix. The results strongly support that Salix. Toisusu and Chosenia form a monophyletic group, confirming the merge of Toisusu and Chosenia with Salix. Within Salix s.l., two major clades are recognizable; one contains species of subgenus Salix (excluding sections Triandrae and Urbanianae), with the New World and the Old World species forming strongly supported clades, respectively; and the other includes sections Triandrae, Urbanianae, Chosenia and all species of subgenera Chamaetia and Vetrix, with the latter two subgenera forming a robustly supported subclade but with low resolution. A new infrageneric classification of Salix is herein proposed. The previously recognized subgenus Salix is split into three subgenera: Salix, Chosenia and Triandrae, and subgenera Chamaetia and Vetrix are combined as subgenus Vetrix.

The phylogenetic relationships of Nolana (Nolaneae, Solanaceae) were constructed using partial sequences (ca. 891 bp) of the granule-bound starch synthase I (GBSSI) or the waxy gene. Nolana, with 89 species, is primarily distributed in coastal Chile (49 spp.) and Peru (43 spp.), and of these, four species are recorded in Peru and Chile, and another from the Galapagos Islands, Ecuador. Our phylogenetic analysis, utilizing a sampling of 63 of the 89 species, supports the monophyly of Nolana and recovered three clades with 95%-100% bootstrap support. Nolana sessiliflora is the sister taxon to the remainder of the genus. Two large, highly supported clades are evident; one containing taxa from Chile, Peru and the Galapagos Islands, and another containing taxa from Chile and Peru. Nolana galapagensis, an endemic to the Galapagos Islands, is suggested to be sister to N. arenicola in a clade that also includes N. adansonii from southern Peru and northern Chile. These two species differ substantially in habitat preference, habit, leaf shape, and mericarp morphology. The monophyly is confirmed for a morphologically cohesive group composed of N. acuminata, N. baccata, N. elegans, N. reichei, N. parviflora, N. pterocarpa, and N. paradoxa, a clade of essentially Chilean species.

Trevesia vietnamensis J. Wen & P.K. L?c (Araliaceae) is described as an unusual new species from northwestern Vietnam. This species has 4?5-merous flowers with a 4-5-locular ovary and palmately compound leaves and would thus fit well within Brassaiopsis morphologically. Phylogenetic analysis using the nuclear ribosomal ITS and the chloroplast ndhF and trnL-F sequences, however, clearly places the new taxon in Trevesia, defined to include species with 6-16-merous flowers with 6-16-locular ovaries, and palmately lobed simple leaves. The discovery of Trevesia vietnamensis thus blurs the generic boundary between Trevesia and Brassaiopsis. The phylogenetic analysis suggests a sister-species relationship between Trevesia vietnamensis and T. lateospina from northern Thailand, a finding supported by a shared morphological character?the presence of setose hairs on the inflorescences and young stems. Trevesia vietnamensis is restricted to two localities in northwestern Vietnam. It grows in limestone areas in valleys and on shady mountain slopes at 500-700 m in primary, tropical, monsoon, broad-leaved forests.

Stachyuraceae consist of a single genus Stachyurus with about ten species endemic to eastern Asia. The family was recently shown to be sister to the western North American Crossosomataceae. The phylogeny of Stachyuraceae and its relatives was reconstructed based on sequences of four chloroplast DNA regions (trnL intron and adjacent trnL-trnF spacer, rpsl6 intron, ndhF gene, trnS-trnG-trnG region) and the nuclear ribosomal ITS region. The monophyly of Stachyurus was strongly supported. The divergence time between Stachyuraceae and Crossosomataceae was estimated to be 68.25 ± 10.36 million years ago (MYA) using the penalized likelihood method based on rbcL sequences data with fossil calibration. Stachyurus sigeyosii was previously synonymized as S. himalaicus, but our analysis shows that it is sister to the morphologically highly distinct S. praecox from Japan and does not form a clade with S. himalaicus.

Chromosome numbers of 45 accessions representing 16 genera and 37 species of Araliaceae are herein reported, of which 30 species and seven genera (Apiopetalum, Arthrophyllum, Delarbrea, Merrilliopanax, Metapanax, Myodocarpus, and Pseudosciadium) are recorded for the first time. The evolution of this character is also examined in light of recent hypotheses of phylogenetic relationships. Chromosome numbers in the family are relatively uniform, generally with 2n = 24 or 48. However, the genus Hedera exhibits extreme variability, with a polyploid series ranging from 2n = 48 to 192. The basic number of Araliaceae is inferred to be x = 12, although x = 6 cannot be ruled out. The "Asian palmate" clade, the largest of the three major clades of core Araliaceae, is primarily characterized by polyploidy, although several genera have sometimes been regarded as evolutionarily "primitive". By contrast, Aralia, Panax, and Polyscias (representing other major clades within the family) include species with both diploids and tetraploids. Four genera recently segregated from core Araliaceae (Apiopetalum, Delarbrea, Myodocarpus, and Pseudosciadium) are reported as n = 12. The formerly apiaceous Hydrocotyle (now placed in Araliaceae) is best interpreted as x = 12, although some aneuploid species may exist with x = 9. Hydrocotyle also exhibits extensive variation in ploidal level. Within Araliaceae, chromosomal variation is largely related to ploidal level, with relatively few cases of aneuploidy, such as those documented in Panax ginseng and Hydrocotyle. The available data are largely consistent with the hypothesis that the basic chromosome number of Apiales is x = 6.

Sequence data from a portion of the Granule-Bound Starch Synthase I (GBSSI) gene or waxy, were used to infer the phylogeny of the core Asian Araliaceae clade. The amplified region included exons 10 and 11 together with the intervening intron. The level of intrageneric variation was low (∼2%) relative to that among genera (4-5%). Two main paralogous copies of waxy were revealed by sequencing cloned PCR products for Oreopanax floribundum, O. capitatus, Tetrapanax papyrifer, and Schefflera delavayi, which might be the result of gene duplication or polyploidy. Analyses based on parsimony, maximum likelihood and Bayesian methods supported several clades, including Brassaiopsis with Thevesia, Macropanax with Metapanax, Eleutherococcus with Kalopanax, and Panax with Aralia. Analyses also suggested a possible relationship between Tetrapanax papyrifer and Schefflera delavayi within the Asian core Araliaceae. The waxy phylogeny was largely congruent with the topologies based on previous analyses of nuclear ribosomal ITS and chloroplast ndhF data. The phylogenetic inference from each waxy copy was similar, although both copies were not recovered for all species sampled. It is concluded that with special consideration and care given to detecting and accounting for the presence of multiple copies, waxy can provide information within Araliaceae. However, efforts should now be directed towards exploring a larger portion of the gene, particularly the 5' region.

Parashorea chinensis Wang Hsie and Parashorea chinensis var. kwangsiensis Lin Chi (Dipterocarpaceae) are economically and ecologically important tree taxa in China and Vietnam. Their authorship should be "Wang Hsie" and "Lin Chi", respectively, which represent two logograms of working groups that existed in the particular circumstances from the 1960s to the 1970s in China. The author of Parashorea chinensis has sometimes been designated inappropriately as H. Wang. We herein discuss in detail these two unique cases in the context of the International Code of Botanical Nomenclature.

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