Fruiting body-guided molecular identification of root-tip mantle mycelia provides strong indications of ectomycorrhizal associations in two species of Sistotrema (Basidiomycota)

Fruiting body guided sequence analysis of mycorrhizal root-tip mycelia is a powerful yet relatively sparsely explored method for species-level identification of mycorrhizal fungi. It is used in this study to indicate mycorrhizal associations in the corticioid (resupinate) genus Sistotrema of the cantharelloid clade through phylogenetic analysis of the ITS and nuLSU rDNA regions of two spatiotemporally co-occurring Sistotrema fruiting bodies and ectomycorrhizal root tips. The genus Sistotrema is confirmed to be polyphyletic, and the mycorrhizal species form a strongly supported monophyletic clade together with the stipitate genus Hydnum. The remaining lineages of Sistotrema may well be saprotrophic, the nutritional mode traditionally attributed to the genus, but the phylogenetic analyses show that they should be excluded from Sistotrema. The cantharelloid clade contains several mycorrhizal genera, but no symbiotic associations have previously been demonstrated for Sistotrema.     

Analysis of phylogenetic relationships of Potamogeton species in China based on chloroplast trnT-trnF sequences

Sequences of the chloroplast trnT-trnF region were analyzed for species of the genus Potamogeton distributed in China to reconstruct phylogenetic relationships. The phylogenetic analyses showed that the genus Potamogeton could be divided into two clades. Eighteen species formed a monophyletic clade while the remaining four formed a second, distinguishable one, supporting the conventional treatment that the genus Potamogeton contains the submerged linear-leaved group and the submerged broad-leaved group. The first clade, which represented the subgenus Potamogeton, could be further divided into two subclades. The second clade, which represented the subgenus Coleogeton, displayed a close phylogenetic relationship with the subgenus Potamogeton and occupied a unique position within the genus Potamogeton. This finding suggested that the treatment of the subgenus Coleogeton, which was once regarded as the genus Stuckenia Börner, may need to be reconsidered. Furthermore, identification of maternal donors of some hybrids was successfully applied based on sequence of maternally inherited chloroplast genome. The female parents of three putative hybrids, P. × malainoides, P. × anguillanus, and P. × orientalis, were proved to be accordant with previous morphological conclusions.     

Molecular phylogeny and systematic in the genus Brachycaudus (Homoptera: Aphididae): insights from a combined analysis of nuclear and mitochondrial genes

Phylogenetic relationships among members of the Aphid genus Brachycaudus (Homoptera: Aphididae) were inferred from partial sequences of mitochondrial cytochrome B oxidase (CytB), two partial fragments of mitochondrial cytochrome C oxidase subunit I (COI) and the internal transcribed spacer II (ITS2) of ribosomal DNA. Twenty-nine species, with several specimens per species, were included, representing all the historically recognized species-groups and subgenera used in the genus except the monospecific subgenus Mordvilkomemor. Results indicate that the genus Brachycaudus is a well-supported monophyletic group. While our results validate the monophyly of subgenera Thuleaphis , Appelia and Brachycaudus s. str. , they reveal two discrepancies in the classical taxonomy. First, the monotypic subgenus Nevskyaphis does not appear valid. Second, the traditionally defined Acaudus subgenus is not monophyletic. On the other hand, our phylogenetic trees corroborate Andreev's recent definition of Acaudus and Brachycaudina. However, they clearly show that the subgenera Prunaphis , Nevskyaphis and Scrophulaphis as defined by this author do not form monophyletic groups. Our results also highlight a highly supported clade that has not been discussed by previous authors; this clade could form a new subgenus, the subgenus Nevskyaphis . Finally, our study shows that molecular data and morphology meet the same limits in delimiting species groups and species themselves. Species groups in which taxonomic treatment is difficult are polytomous. Furthermore, except for one node clustering Brachycaudus s. str . and Appelia, intersubgeneric relationships remain poorly resolved even when several genes are added to the phylogenetic analysis. These results, together with previous studies in other aphid groups suggest that diversification might have been a rapid process in aphids.     

中国榕属榕亚属植物的系统发育初探

对分布于中国的榕亚属植物的15个种和2个变种(分别代表榕亚属的3个组)的nrDNA的ITS序列和系统发育关系进行分析。结果表明,榕亚属是非单系起源,其中榕组构成了一个独立的单系群,与无花果亚属有较近的亲缘关系,而与榕亚属其它组间并未表现出近缘关系。榕亚属的其它5个组构成一单系群并得到中度的支持率。来自中国的种类分别聚在相应的组内。但环纹榕组被分成2个单支,其中来自中国的大叶水榕(F.glaberrima)和环纹榕(F.annulata)构成一个分支,二者表现较近的亲缘关系。榕亚属的亚洲特有组印度榕组在ITS树中聚在环纹榕组的另一个分支中,但它与此组其它种的亲缘关系并不清楚。     

Phylogenomic relationships and species identification of the olive genus Olea (Oleaceae)

The olive genus Olea includes c. 30–40 taxa in three subgenera (Olea, Tetrapilus, and Paniculatae) within the family Oleaceae. Historically, the Olea genus was classified into four groups that were overall well supported by reconstructed phylogenies, despite incomplete sampling of subgenus Tetrapilus and poor resolution within clades. These analyses also showed that the genus was not monophyletic. Reliable identification of Olea species is important for both their conservation and utilization of this economically important genus. In this study, we used phylogenomic data from genome skimming to resolve relationships within Olea and to identify molecular markers for species identification. We assembled the complete plastomes, and nrDNA of 26 individuals representing 13 species using next-generation sequencing and added 18 publicly available accessions of Olea. We also developed nuclear SNPs using the genome skimming data to infer the phylogenetic relationships of Olea. Large-scale phylogenomic analyses of 138 samples of tribe Oleeae supported the polyphyly of Olea, with Olea caudatilimba and Olea subgenus Tetrapilus not sharing their most recent common ancestor with the main Olea clade (subgenus Paniculatae and subgenus Olea). The interspecific phylogenetic resolution was poor owing to a possible rapid radiation. By comparing with the plastome data, we identified the markers ycf1b and psbE-petL as the best Olea-specific chloroplast DNA barcodes. Compared with universal barcodes, specific DNA barcodes and super-barcode exhibited higher discriminatory power. Our results demonstrated the power of phylogenomics to improve phylogenetic relationships of intricate groups and provided new insights into barcodes that allow for accurate identification of Olea species.     

Phylogenetic relationships among Bactrocera species (Diptera: Tephritidae) inferred from mitochondrial DNA sequences

Several members of the dipteran family Tephritdae are serious pests because females lay eggs in ripening fruit. The genus Bactrocera is one of the largest within the family with over 500 described species arranged in 28 subgenera. The phylogenetic relationships among the various species and subgenera, and the monophyly of specific groups have not been examined using a rigorous phylogenetic analysis. Therefore, phylogenetic relationships among 24 Bactrocera species belonging to 9 subgenera were inferred from DNA sequence of portions of the mitochondrial 16S rRNA, cytochrome oxidase II, tRNA(Lys), and tRNA(Asp) genes. Two morphological characters that traditionally have been used to define the four groups within the subgenus Bactrocera were evaluated in a phylogenetic context by mapping the character states onto the parsimony tree. In addition, the evolutionary trend in male-lure response was evaluated in a phylogenetic context. Maximum parsimony analyses suggested the following relationships: (1) the genus Bactrocera is monophyletic, (2) the subgenus B. (Zeugodacus) is paraphyletic, (3) the subgenus B. (Daculus) is a sister group to subgenus B. (Bactrocera), and (4) the subgenus B. (Bactrocera) is monophyletic. The mapping analyses suggested that the morphological characters exhibit a simple evolutionary transition from one character state to another. Male-lure response was identified as being a labile behavior that has been lost on multiple occasions. Cue-lure response was plesiomorphic to methyl-eugenol response, and the latter has evolved independently within the Bactrocera and Zeugodacus groups of subgenera. The implications of our results for devising a coherent, consolidated classification for Bactrocera is discussed.     

Species of Colletotrichum on Agavaceae

Species of Colletotrichum cause diseases on a wide range of hosts, frequently infecting plants in the Agavaceae (monocotyledons: Liliales). Three species of Colletotrichum restricted to the Agavaceae were detected through morphological studies of specimens and molecular sequence analyses of the LSU of the nu-rDNA and the ITS region of the nu-rDNA from cultures. Colletotrichum agaves on Agave is fully described and illustrated. Colletotrichum dracaenophilum is described as a new species for isolates having long conidia and occurring on Dracaena sanderiana from China. Colletotrichum phormii and Glomerella phormii are determined to be the correct scientific names for the asexual and sexual states, respectively, of a species commonly referred to as C. rhodocyclum and G. phacidiomorpha occurring mainly on Phormium. In addition, C. gloeosporioides and C. boninense were isolated from plants in the Agavaceae. All species of Colletotrichum described on Agavaceae were evaluated based on type specimens. A key to the five species of Colletotrichum on Agavaceae is included. This paper includes one new species, Colletotrichum dracaenophilum, and three new combinations, Colletotrichum phormii, Glomerella phormii, and Phaeosphaeriopsis phacidiomorpha.     

Phylogenetic relationships within Pyrenodesmia sensu lato and the role of pigments in its taxonomic interpretation

Most lichens of the family Teloschistaceae (Ascomycota) produce yellow-orange-red anthraquinone pigments. However, the genus Pyrenodesmia encompasses species in which anthraquinones are absent and replaced by a gray pigment Sedifolia-gray. It was shown recently that these species are related to taxa with both anthraquinones and Sedifolia-gray (Caloplaca xerica group, C. haematites group, and C. cretensis) and to species with a brown pigment instead of both anthraquinones and Sedifolia-gray (C. demissa, C. obscurella, and C. reptans). Nevertheless, relationships between mentioned anthraquinone-containing and anthraquinone-lacking species remained unclear. In total, 8 DNA loci from 41 species were used here to resolve these uncertainties. We concluded that C. demissa, C. obscurella, and C. reptans are rather distant from the core of Pyrenodesmia, and we place them outside of Pyrenodesmia sensu lato. Within Pyrenodesmia sensu lato, three lineages were revealed and recognized on a generic level: the genus Pyrenodesmia sensu stricto (21 species), the genus Kuettlingeria (14 species), which is resurrected here, and the genus Sanguineodiscus (4 species), which is newly described here. The genus Pyrenodesmia includes taxa that never contain anthraquinones, but Sedifolia-gray. It matches with the former C. variabilis group. Taxa of the genera Kuettlingeria and Sanguineodiscus have anthraquinones in their apothecia and Sedifolia-gray in their thalli. The genus Kuettlingeria includes the former C. xerica group plus C. cretensis and C. diphyodes. The genus Sanguineodiscus includes the former C. haematites group and C. bicolor. The identity of Kuettlingeria (Caloplaca) diphyodes was clarified and the name Pyrenodesmia helygeoides was resurrected. Twenty-four new combinations were proposed.     

基于ITS序列对中国簇毛黄耆亚属（黄耆属）系统学问题的初步研究

测定了簇毛黄耆亚属（Pogonophace)4组8种和外类群Caragana roborovskyi的ITS序列,从GenBank中调出相关12属47种的ITS序列,组成数据距阵,应用PAUP程序中的最大简约法构建了系统发育树状图。扁荚组（Sect.Sesbanella)与亚属其余类群在系统树上处于不同的分支,亲缘关系较远这个亚属不是一个单系类群;膨果组（Sect.Bibracteola)。背扁组（Sect.Phyllolobium)和袋果组（Sect.Trichostylus)作为一个单系类群能得到ITS序列的支持,但与分组以及膨果组下系的划分都得不到ITS序列分析的支持。     

Delineation of Chondrus (Gigartinales, Florideophyceae) in China and the origin of C. crispus inferred from molecular data

Complete nuclear ribosomal DNA (nrDNA) internal transcribed spacer (ITS) sequences were obtained for 18 Chondrus populations collected at 15 sites from eight countries worldwide. Pairwise comparisons with the multiple alignment revealed that intraspecific divergences of ITS sequences ranged from 0.3 to 1.8% in C. crispus Stackhouse (except for the entity SVLH from France) and from 0.0 to 0.6% in C. ocellatus Holmes, whereas interspecific divergences in Chondrus varied from 1.4 to 5.0%. Three phylogenetic methods (neighbour joining, maximum parsimony and maximum likelihood) confirmed three main lineages: the North Atlantic lineage containing entities of C. crispus from Canada, France, Germany, England, Portugal, Ireland and Wales; a second lineage comprising three species: C. sp. 1, C. armatus (Harvey) Yamada et Mikami, and C. pinnulatus (Harvey) Okamura from the Northern Pacific; and a third lineage containing just one species: C. ocellatus from the Northern Pacific. Chondrus yendoi Yamada et Mikami separated from other Chondrus species singly. nrDNA ITS data indicate that a previous assignment of C. sp. 2 to Mazzaella japonica (Mikami) Hommersand may be incorrect, and additional evidence is needed to resolve the generic placement of this entity. It is inferred from the nrDNA ITS data that three Chondrus species are presently known in China with two, C. ocellatus and C. nipponicus, in Qingdao and two, C. armatus and C. nipponicus, in Dalian. We hypothesize that the ancestor of North Atlantic C. crispus had a Pacific origin, and that the present distribution of C. crispus in the Atlantic Ocean correlates with a trans-Arctic dispersal and vicariance events associated with Pleistocene glaciation maxima.     

舌鳎亚科鱼类单系起源和同种异名的线粒体DNA证据

舌鳎亚科鱼类因形态特征的特殊性, 其分类及系统发育关系一直存在争议。本研究测定了中国沿海14种舌鳎亚科鱼类线粒体DNA的16S rRNA和Cyt b基因的部分片段。两个基因构建的舌鳎亚科系统发育树结果显示, 中国沿海舌鳎亚科鱼类为明显的单系群, 但舌鳎亚科鱼类内部的系统发育关系与形态分类划分的亚属并不完全一致, 日本须鳎(Paraplagusis japonica)与其他舌鳎属(Cynoglossus)种类并未形成不同的分支。虽然舌鳎属内的舌鳎亚属(Cynoglossus)、拟舌鳎亚属(Cynoglossoides)和三线舌鳎亚属(Areliscus)均可以聚为独立分支, 但长吻红舌鳎(C. lighti)与短吻红舌鳎(C. joyneri)、短吻三线舌鳎(C. abbreviatus)与紫斑舌鳎(C. purpureomaculatus)、半滑舌鳎(C. semilaevis)与窄体舌鳎(C. gracilis)及褐斑三线舌鳎(C. trigrammus)这三组物种可能存在同种异名现象。这一结果提示, 基于形态学对舌鳎亚科的种属分类鉴定尚存在不足, 线粒体DNA的系统发育关系可为其分类的修订提供有意义的参考和佐证。     

中国靴耳属6个新种

本文在形态学及分子系统学基础上,对6个采自云南、广西、福建和江西的靴耳属新种进行描述,分别命名为齿缘靴耳、异囊靴耳、假黏靴耳、网孢靴耳、条纹靴耳和毛缘靴耳,并编制中国靴耳属已知物种检索表。基于已知的靴耳属ITS序列,对靴耳属的系统发育分析表明球孢亚属是并系群,并确定了锁状联合的有无及菌盖表皮是否具有凝胶层是靴耳亚属的主要分类特征。     

Phylogeny of Rubus (rosaceae) based on nuclear ribosomal DNA internal transcribed spacer region sequences

We used nuclear ribosomal DNA internal transcribed spacer region (ITS 1 - 5.8S - ITS 2; ITS) sequences to generate the first phylogeny of Rubus based on a large, molecular data set. We sampled 57 taxa including 20 species of subgenus Rubus (blackberries), one to seven species from each of the remaining 11 subgenera, and the monotypic and closely related Dalibarda. In Rubus, ITS sequences are most informative among subgenera, and variability is low between closely related species. Parsimony analysis indicates that Rubus plus Dalibarda form a strongly supported clade, and D. repens may nest within Rubus. Of the subgenera with more than one species sampled, only subgenus Orobatus appears monophyletic. Three large clades are strongly supported: one contains all sampled species of nine of the 12 subgenera; another includes extreme Southern Hemisphere species of subgenera Comaropsis, Dalibarda, and Lampobatus; and a third clade consists of subgenus Rubus plus R. alpinus of subgenus Lampobatus. Rubus ursinus appears to be a hybrid between a close relative of R. macraei (subgenus Idaeobatus, raspberries) and an unidentified subgenus Rubus species. ITS sequences are generally consistent with biogeography and ploidy, but traditionally important morphological characters, such as stem armature and leaf type, appear to have limited phylogenetic value in Rubus.     

A yeast clade near Candida kruisii uncovered: nine novel Candida species associated with basidioma-feeding beetles

Yeasts similar to Candida kruisii were isolated repeatedly from the digestive tracts of basidioma-feeding beetles, especially nitidulids inhabiting and feeding on a variety of agarics in the southeastern USA and Barro Colorado Island, Panama. Based on the identical sequences of the D1/D2 domains of the LSU rRNA gene (rDNA) and host beetle information, the isolates were grouped into 19 genotypes which varied from C. kruisii by up to 38 nucleotide differences in the D1/D2 region. Phylogenetic analysis of rDNA sequences and phenotypic traits placed the isolates in C. kruisii and in nine undescribed taxa. The new species and type strains are designated as Candida pallodes (NRRL Y-27653^T), C. tritomae (NRRL Y-27650^T), C. panamensis (NRRL Y-27657^T), C. lycoperdinae (NRRL Y-27658^T), C. atbi (NRRL Y-27651^T), C. barrocoloradensis (NRRL Y-27934^T), C. aglyptinia (NRRL Y-27935^T), C. stri (NRRL Y-48063^T), and C. gatunensis (NRRL Y-48064^T). A phylogeny based on analysis of a combined database of sequences of SSU and LSU rDNA and the ITS region showed that the nine new species formed a novel sister clade to C. kruisii that was strongly supported by bootstrap analysis. Candida pallodes, C. tritomae, C. panamensis, and C. lycoperdinae formed one subclade, while C. atbi, C. barrocoloradensis, C. aglyptinia, C. stri, and C. gatunensis formed a second distinct subclade within the larger clade. Candida pallodes and C. atbi showed a strong host specificity to beetle species in the genus Pallodes (Coleoptera: Nitidulidae) collected from a variety of agarics. On the other hand, C. panamensis, C. tritomae, and C. lycoperdinae were associated with several unrelated beetles in Erotylidae, Scarabaeidae, Tenebrionidae, and Curculionidae as well as Lycoperdina ferruginea (Nitidulidae). Candida pallodes, C. tritomae, C. lycoperdinae, and C. atbi have been isolated repeatedly in the USA, while the other five new species have been found only at Barro Colorado Island, Panama.     

Molecular phylogenetic studies show Omphalina giovanellae represents a new section of Clitopilus (Agaricomycetes)

After reconsidering the specific characters of Omphalia giovanellae and applying data from the sequences of the D1–D2 domain of the 28S rRNA gene and the ITS region of material collected in Italy and Spain, the species is ascribed to the genus Clitopilus. Considering the rather peculiar characters, especially the smooth spores, C. giovanellae is ascribed to the new section Omphaloidei sect. nov. The species is illustrated with drawings of fresh basidiomata observed in situ, as well as with SEM micrographs of the spores. Also based on DNA sequence data, O. farinolens, recently described from Spain, is shown to be a synonym of C. giovanellae.     

Evolution in Carex L. sect. Spirostachyae (Cyperaceae): A molecular and cytogenetic approach

Carex sect. Spirostachyae comprises 25 species displaying the centre of diversity in Eurasia. Phylogenetic analysis of the ITS nrDNA region of 20 species of sect. Spirostachyae, six species of sect. Ceratocystis, five species of sect. Elatae, and eight outgroup species reveals that neither sect. Spirostachyae nor sect. Elatae is monophyletic. With the exclusion of Carex cretica, the 19 species of sect. Spirostachyae studied form a clade with the five species of tropical-subtropical sect. Elatae. Taxonomy of the core Spirostachyae is not only mostly in agreement with our phylogenetic hypothesis, but also with ecological and new cytogenetic results. Two main groups with different chromosome numbers and edaphic preferences are identified in the core Spirostachyae. One includes primarily acidophilous species with high chromosome numbers (2n=(64)68–84), whereas the other one includes mainly basophilous species with lower chromosome numbers (2n=60–74(75)). Chromosome-number variation is extremely different in the core Spirostachyae, showing great stability in some widespread species (e.g. Carex extensa) but an active chromosome evolution – faster chromosomal rearrangements, fusion and fission events than ITS nucleotide substitutions – in more restricted species (e.g. Carex troodi). Biogeography of the two amphiatlantic pairs of species reveals two independent colonizations of South America from the European continent. The geographical barrier of the Strait of Gibraltar has played different roles in the course of evolution of this section, acting as an effective barrier to gene flow in one case (Carex helodes) but as a limited barrier or recent separation in two others (Carex distans, Carex punctata).     

A novel group I intron in Candida dubliniensis is homologous to a Candida albicans intron

In the present study, we determined the sequence of group I self-splicing introns found in the large ribosomal RNA subunit of Candida albicans, Candida stellatoidea and the recently-described species Candida dubliniensis. It was found that both the intron and ribosomal RNA nucleotide sequences are almost perfectly identical between different C. albicans strains as well as between C. albicans and C. stellatoidea strains. Comparisons of ribosomal RNA sequences suggest that local isolates of atypical C. albicans from individuals infected with human immunodeficiency virus can be assigned to the C. dubliniensis species. C. dubliniensis strains also harbor a group I intron in their ribosomal RNA, as observed in about 40% of C. albicans strains and all C. stellatoidea strains. This novel C. dubliniensis group I intron is identical to the C. albicans and C. stellatoidea intron, except for two widely divergent stem-loop regions. Despite these differences, the C. dubliniensis intron possesses self-splicing ability in an in vitro assay. Taken together, these data support the idea that C. albicans and C. stellatoidea should be joined together as variants of the same species while C. dubliniensis is a distinct but closely related microorganism. To our knowledge, the C. albicans and C. dubliniensis introns are the first example of a pair of homologous group I introns differing only by the presence of apparently facultative sequences in some stem-loops suspected to be involved in stabilization of tertiary structure.     

A phylogeny of all species of Arceuthobium (Viscaceae) using nuclear and chloroplast DNA sequences

The genus Arceuthobium (dwarf mistletoes, Viscaceae) comprises 42 species that parasitize hosts in Pinaceae and Cupressaceae in the Old and New Worlds. Maximum parsimony analyses were conducted on two data partitions (separately and combined): nuclear ribosomal internal transcribed spacer (ITS) sequences for all 42 currently recognized species and chloroplast trnT-L-F sequences for 34 New World species. The Old and New World species were phylogenetically distinct using ITS, thus making subgenus Arceuthobium paraphyletic. Arceuthobium pendens and A. guatemalense comprise the basalmost clade of subgenus Vaginata, characterized by the presence of flabellate secondary branching. The trnT-L-F sequences, which vary widely in length depending upon taxon, contain three times less phylogenetic signal than ITS, although homoplasy for this partition is lower. Several of the clades obtained from analysis of nuclear ITS sequences are also recovered using trnT-L-F sequences such as A. guatemalense and A. pendens, the A. rubrum group, the A. vaginatum group, and the A. campylopodum group. The ITS + trnT-L-F tree is well resolved except for four internal nodes. A revised classification of the genus is discussed that recognizes only monophyletic species that are well differentiated by molecular data.     

Genetic relationship between Salix exigua and other North American willows (Salix L.): Evidence from allozyme variation

Starch gel electrophoresis was used to examine the allozyme variation and the genetic relationship between Salix exigua and other North American willows. A total of 149 clonal collections comprising six willow species were analyzed for 26 putative isozyme loci. Genetic distances between species were estimated and used for distance analysis of species relationships. Individual alleles were used as characters for cladistic analysis of phylogenetic inference. Distance analysis indicates that S. exigua has approximately equal divergence to both subgenus Salix and Vetrix. Results of cladistic analysis suggest that S. exigua may be a separate group isolated from all other willows. Based on evidence of allozyme variation, it is suggested that the taxonomic placement of S. exigua within subgenus Salix need to be revised.     

Phylogeny and infrageneric classification of Symplocos (Symplocaceae) inferred from DNA sequence data

Symplocos comprises ～300 species of woody flowering plants with a disjunct distribution between the warm-temperate to tropical regions of eastern Asia and the Americas. Phylogenetic analyses of 111 species of Symplocos based on the nuclear ribosomal internal transcribed spacer (ITS) region and the chloroplast genes rpl16, matK, and trnL-trnF yielded topologies in which only one of the four traditionally recognized subgenera (Epigenia; Neotropics) is monophyletic. Section Cordyloblaste (subgenus Symplocos; eastern Asia) is monophyletic and sister to a group comprising all other samples of Symplocos. Section Palura (subgenus Hopea; eastern Asia) is sister to a group comprising all other samples of Symplocos except those of section Cordyloblaste. Symplocos wikstroemiifolia (eastern Asia) and S. tinctoria (southeastern United States), both of subgenus Hopea, form a clade that groups with S. longipes (tropical North America) and the species of subgenus Epigenia. The remaining samples of subgenus Hopea (eastern Asia) form a clade. Section Neosymplocos (subgenus Microsymplocos; Neotropics) is well nested within a clade otherwise comprising the samples of section Symplocastrum (subgenus Symplocos; Neotropics). Section Urbaniocharis (subgenus Microsymplocos; Antilles) groups as sister to the clade comprising Symplocastrum and Neosymplocos. The data support the independent evolution of deciduousness among section Palura and S. tinctoria. The early initial divergence of sections Cordyloblaste and Palura from the main group warrants their recognition at taxonomic levels higher than those at which they are currently placed. An inferred eastern Asian origin for Symplocos with subsequent dispersal to the Americas is consistent with patterns from other phylogenetic studies of eastern Asian-American disjunct plant groups but contrary to a North American origin inferred from the earliest fossil occurrences of the genus.