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Central Asia, especially the Tian‐Shan and Pamir‐Alay, is a biodiversity hotspot for Hedysarum(Fabaceae) with a high number of endemic species. However, to date, studies of the genus Hedysarumbased on molecular data have included only a few species distributed in this region. To fill this gap, we analysed 110 Hedysarumspecies, 36 of which were from the Tian‐Shan and Pamir‐Alay Mountains of Central Asia. We performed phylogenetic analyses, divergence time estimates, and biogeographic analyses using both the internal transcribed spacers of nuclear ribosomal DNA (nrDNA ITS) and three plastid DNA (cpDNA) sequences (trnL‐trnF, matK, psbA‐trnH). Our phylogenetic analysis grouped the species of Hedysaruminto three sections: H.sect. Hedysarum, sect. Multicaulia, and sect. Stracheya, which are largely consistent with previous phylogenetic classifications. Accordingly, most of the Central Asian species we studied (28 spp.) were placed in H. subsect. Criniferawithin H. sect. Multicaulia. Our divergence time and biogeographic analyses indicate that Hedysarumlikely originated in West Asia and/or East Asia during the Early Miocene or Middle Miocene and subsequently dispersed to adjacent areas of Eurasia, as well as North America via the Bering Land Bridge. The likely area of origin for H. sect. Multicauliais West Asia, while East Asia appears to be the center of origin for H.sect. Hedysarumand sect. Stracheya. In addition, we suggest that the rapid radiation of the species of H. subsect. Criniferaoccurred in the Tian‐Shan and Pamir‐Alay Mountains, as well as the Turkish‐Iranian Plateau, and that geological and climatic changes were the main causes of speciation in Hedysarum.

Despite the well‐known biogeographic pattern in the Northern Hemisphere of disjunct distributions in plants between eastern Asia and North America, many details regarding the evolution of the disjunction between lineages of tropical Asia and tropical America remain poorly understood. Berchemia(Rhamnaceae), comprising ca. 32 species, is distributed predominantly in tropical regions of east to southeast Asia and North America. However, the phylogeny and biogeography of this genus are still not clear. Furthermore, fossils of the genus have been found in Europe, making it an ideal group to understand the biogeographical story of tropical disjunction in the Northern Hemisphere. With two nuclear (ETS, ITS) and three plastid (petA‐psbJ, psbA‐trnH, trnL‐F) DNA regions, we first reconstructed the phylogeny of Berchemiawith Bayesian inference and maximum likelihood approaches. Our results indicated that Berchemia, excluding the African species B. discolorand B. zeyheri, which were placed into the reinstated Phyllogeiton, was well‐supported as monophyletic. Divergence times and ancestral areas were inferred using a Bayesian uncorrelated lognormal relaxed molecular clock model and Bayesian binary MCMC method, respectively. The core Berchemialikely originated in the Western Tethys during the middle Eocene, then formed the tropical Asia and tropical America disjunction during the Oligocene and further diversified in Asia from the early Miocene on. The formation and diversification of the core Berchemialikely resulted from a mixture of geologic events, such as the close of the Tethys Ocean, disappearance of the North Atlantic Land Bridges, uplift of the Qinghai‐Tibetan Plateau, and climatic events, such as the establishment and enhancement of Asian monsoons.

Cushion plants exhibiting adaptive convergence in cold and dry environments are keystone and foundation species in the alpine/subnival habitat on the Qinghai‐Tibet Plateau (QTP). To date, little attention has been paid to the molecular phylogeny, origin, and biogeography of cushion plants on the QTP. We investigated the molecular phylogeny of classic cushion Arenariasubg. Dolophragma, A. subg. Eremogoneastrum, and Thylacospermumon the QTP, within the framework of the Caryophyllaceae. A new Thylacospermum‐Dolophragma clade was identified using combined plastid markers (rps16, matK, trnL‐trnF, trnS‐trnfM) and nuclear ribosomal DNA. Molecular divergence dating suggested that Thylacospermumand A. subg. Dolophragmaoriginated in the middle to late Miocene (11.68 Ma). Combined with ancestral range reconstruction, there is an indication that all species of cushion Arenaria(A. subg. Dolophragma, A. subg. Eremogoneastrum) originated during/after the late Pliocene, and the QTP was their ancestral area. Furthermore, ecological niche modeling showed that the areas occupied by the three studied cushion plants during the last glacial maximum (LGM) was broader than that of their present distribution, implying a reduction in their range after the LGM. This evidence clearly illustrates that multistage uplift of the QTP and bordering mountains since the Miocene associated with climatic change (worldwide cooling, aridification in Central Asia, Quaternary glaciation) played a role in triggering and facilitating the speciation and/or evolutionary radiations of the species studied.

Pyrulariais a small parasitic genus of the Santalales with two to five species exhibiting a well‐known classical intercontinental disjunct distribution between eastern Asia (EA) and eastern North America (ENA). Pyrulariaand another santalaceous genus Buckleyarepresent the only two parasitic plant lineages with the EA–ENA disjunction. The present study was carried out to assess the species number and molecular and morphological differentiation in Pyrularia, and to reconstruct the biogeography of the Pyrulariaclade (Pyrulariaand its close allies) using dating and biogeographic inferences. A phylogenetic analysis based on two nuclear and seven plastid markers strongly supported the monophyly of Pyrulariaand revealed two highly distinct subclades corresponding to EA and ENA within the genus. Incongruent topologies within the eastern Asian lineage were found between the nuclear and the plastid datasets, which may be attributed to incomplete lineage sorting. Morphometric and phylogenetic analyses suggest that Pyrulariain eastern Asia may best be treated as a single species, P. edulis. Molecular dating based on four markers suggested that the divergence time between the intercontinental species was in the late Miocene at 5.58 Ma (95% HPD: 2.08–11.72 Ma), which was close to the split of the trans‐Pacific clades within the other parasitic EA–ENA disjunct genus Buckleya. The EA–ENA disjunction in the only two parasitic genera may have resulted from the fragmentation of the mesophytic temperate forests in the late Miocene. The Pyrulariaclade (including the close allies of Pyrularia) was inferred to have originated in Africa, then dispersed to Asia, and subsequently to North America via the Bering land bridge, resulting in the current intercontinental EA–ENA distribution of Pyrularia.

Paliurus(Rhamnaceae) is a small genus with a narrow and disjunct distribution in East Asia and the Mediterranean. Fossil evidence from the Late Cretaceous to the present suggests it once had a broad geographic distribution, encompassing parts of India, North America, Asia, and Europe. To reconstruct the evolutionary history of Paliurusand understand the origin of the disjunction observed today in the Northern Hemisphere, phylogenetic and biogeographical reconstructions were performed based on ITS, trnL-F,and rbcLsequences. Paliurusis shown to be a monophyletic genus, which could be divided into two clades as suggested by previous studies. Biogeographical inference integrated with fossil information indicates that the origin and dispersal pattern of the genus coincide with the “Out-of-India” hypothesis. The genus may have originated in India or other parts of Gondwana and then dispersed to East Asia after the collision of the Indian subcontinent with Eurasia, and to North America via the Bering land bridge. Paliurusappears to have reached the Mediterranean region in the late Oligocene following closure of the Turgai Strait. The uplift of the Qinghai-Tibet Plateau and the advent of drying and cooling climates during the Miocene may have fragmented the distribution of the genus, shaping the biogeographical patterns observed today. Paliuruspopulations in different regions either became extinct or adapted to changes in local ecological conditions following global climatic shifts through geological time.

Subtribe Gentianinae, encompassing Gentiana, Tripterospermum, Metagentianaand Crawfurdia, represents one of the most species-rich clades of Gentianaceae. Only a few taxonomic uncertainties have remained at generic level in subtribe Gentianinae: the inclusion of Gentianasect. Otophorain Gentiana, and the polyphyletic nature of Metagentiana. In both cases, data were lacking in earlier studies to resolve ambiguities and provide the baseline for a solid taxonomic treatment of these lineages. For the present study, we increased the number of species sequenced for Gentianasect. Otophoraand Metagentiana, using a combination of nuclear (ITS) and plastid (trnL-F, atpB-rbcL) markers. We reconstructed phylogenetic relationships in Gentianinae conducting maximum likelihood and Bayesian analyses. Our results show that Gentianasect. Otophorais monophyletic and more closely related to Metagentianathan to Gentiana. We suggest excluding Gentianasect. Otophorafrom Gentianaand elevating this group to the rank of genus described here under the name Kuepferia. Metagentianais monophyletic when excluding two species, M. striataand M. souliei, here described as the new genus Sinogentiana.

Salweenia(Leguminosae) has long been defined as a monotypic genus. In this study we carried out comprehensive studies on populations of S. wardiiBaker f. across its distribution range. The results showed that this species diverged into two distinct groups: plants from the Yalong Jiang valley have linear leaflets 0.07–0.14 cm wide and relatively flattened legumes, as well as a 2A karyotype asymmetry, whereas plants from the Nu Jiang and Lancang Jiang drainages have lanceolate leaflets 0.20–0.34 cm wide, undulant legumes, and a 1A karyotype asymmetry. Furthermore, molecular phylogenetic analysis of four chloroplast DNA markers (trnL-F, rpl32-trnL, psbA-trnH, trnS-G) recovered two reciprocally monophyletic clades among accessions of plants from these two areas respectively. We therefore recognize individuals of S. wardiiin the Yalong Jiang valley as a separate species, S. bouffordianasp.nov. Salweeniathus contains two allopatrically distributed species and the genus is no longer monotypic. The origin of the disjunction between the two species is briefly discussed and it is hypothesized to have come about through vicariance, resulting of several historic river separations, reversal and capture events estimated to have taken place during the Pleistocene.

Soroseris, Stebbinsia, and Syncalathiumare 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-Fand psbA-trnHfragments were analyzed with parsimony, Bayesian inference, and relaxed Bayesian dating for all species of Soroseris, Stebbinsia, and Syncalathium. Stebbinsiais part of a polytomy with several lineages of Soroseris. Syncalathiumis biphyletic with Syn. soulieiplaced within subtribe Lactucinae and the remaining species close to the Soroseris-Stebbinsiaclade within subtribe Crepidinae. Bayesian dating based on ITS sequences and using four fossil calibrations suggests that the stem and crown ages of the Soroseris-Stebbinsiaclade and the two groups of Syncalathiumare between 8.44 and 1.56 million years. Stebbinsiashould be treated as a section of Soroserisand Syncalathium soulieishould be excluded from Syncalathiumand either placed in Lactuca s.l. or established as a new genus in Lactucinae. The remaining species are to be treated as Syncalathiums.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-Stebbinsiaclade, allopatric speciation within Syncalathiums.str. and convergent evolution of Syncalathiums.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 rbcLgene, trnD-Tspacer and atpB-rbcLspacer for phylogenetic analyses of Salix. The results strongly support that Salix, Toisusu and Chosenia form a monophyletic group, confirming the merge of Toisusuand Choseniawith Salix. Within Salixs.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, Choseniaand all species of subgenera Chamaetiaand 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 Salixis split into three subgenera: Salix, Choseniaand Triandrae, and subgenera Chamaetiaand Vetrixare combined as subgenus Vetrix.

Sun, H., McLewin, W. & Fay, M. F.: Molecular phylogeny of Helleborus(Ranunculaceae), with an emphasis on the East Asian‐Mediterranean disjunction. ‐ Taxon 50: 1001–1018 2001.‐ISSN 0040–0262. Phylogenetic relationships within the genus Hellebons(Ranunculaceae) were evaluated with analyses of plastid trnL‐Fand partial matKand nuclear ITS DNA sequences for all 16 currently recognised species in addition to several subspecies and geographical variants. The molecular study provides strong support for the monophyly of Helleborus.However, both traditional divisions of the genus, into two groups (Caulescentesand Scapigeri) or two subgenera (Helleborastrumand Helleborus), are refuted. All six currently recognised sections (Dicarpon, Chenopus, Griphopus, Helleborus, Helleborastrum, and Syncarpus) are monophyletic, four by default because they are monospecific. Section Dicarpon(H. thibetanus) is strongly supported as sister group to section Helleborastrumand could therefore be sunk into that section. Relationships between this pair of sections and the other sections are, however, not clear. At the specific level, all species which are clearly distinct morphologically are also distinct in terms of molecular divergence, but relationships between the poorly differentiated species in section Helleborastrumare not resolved with any degree of support. Using a molecular clock based on matKsequence divergence, the disjunction of H. thibetanusand section Helleborastrumbetween East Asia and the Mediterranean is tentatively dated at approximately 23 million years (middle Miocene), which corresponds well with the geological history of the area where H. thibetanusoccurs.