Morphological and molecular evidence reveals three new species of Lithocarpus (Fagaceae) from Bidoup-Nui Ba National Park, Vietnam.

Three new species, Lithocarpusbidoupensis Ngoc & Tagane, L.congtroiensis Ngoc & Yahara, and L.hongiaoensis Ngoc & Binh are described from Bidoup-Nui Ba National Park, Central Highland of Vietnam. Morphological analyses and Maximum likelihood tree based on genome-wide SNPs support the distinction of those species from the previously known taxa in the region. The three new species are considered to be endemic to the Bidoup-Nui Ba National Park and the preliminary conservation status for each species is evaluated as Critically Endangered.

Evaluating the genetic diversity in two tropical leguminous trees, Dalbergia cochinchinensis and D. nigrescens, in lowland forests in Cambodia and Thailand using MIG-seq.

It is vital to measure the levels of genetic diversity and differentiation between populations in a species to understand the current genetic structure and evolution of the species. Here, MIG-seq (multiplexed inter-simple sequence repeat genotyping by sequencing) was employed to assess the genetic variation in two tropical leguminous tree species, Dalbergia cochinchinensis and D. nigrescens, in Cambodia and Thailand. Sequence data for 255-618 loci, each with an approximate length of 100 bp, were obtained, and the nucleotide diversity, Tajima's D and FST were computed. The estimates calculated from the data obtained by MIG-seq were compared to those obtained by Sanger sequencing of nine nuclear coding genes in D. cochinchinensis in our previous study. The nucleotide diversity at the MIG-seq loci was slightly higher than that at silent sites in the coding loci, whereas the FST values at the MIG-seq loci were generally lower than those at the coding loci, although the differences were not significant. Moreover, nucleotide diversities within populations of the two species were similar to each other, at approximately 0.005. Three and four population clusters were genetically recognized in D. cochinchinensis and D. nigrescens, respectively. Although the populations were differentiated from each other, the levels of differentiation among them, as measured by FST, were higher in D. cochinchinensis than in D. nigrescens. This indicates higher levels of gene flow between the populations in the latter species. We recommend using MIG-seq for quick surveys of genetic variation because it is cost-effective and results in smaller variance in the estimates of population genetic parameters.

Comparative phylogeography of two closely related Viola species occurring in contrasting habitats in the Japanese archipelago.

Similar distribution ranges shared by closely related plant species may have been shaped through different migration histories if those species have differing habitat preference. To test this hypothesis, phylogeographical patterns and population genetic structures were compared between two sister Viola species: Viola eizanensis preferring woodland and V. chaerophylloides var. sieboldiana preferring grassland, both being native to the Japanese Archipelago. Amplified fragment length polymorphism (AFLP) was used for phylogenetic reconstruction, together with Bayesian ancestry analysis, AMOVA, analysis of genetic diversity statistics, and analysis of the relative contribution of each population to total diversity. The results indicated that V. eizanensis had two distinct lineages occurring in the western and eastern part of Japan, but such lineages are not distinct in V. chaerophylloides var. sieboldiana. Both species exhibited the low genetic diversity and high between-population differentiation typical of selfing plants. In V. chaerophylloides var. sieboldiana, one particular population made a significantly higher contribution to the total heterozygosity (H (T)), whereas in V. eizanensis, no population was identified as making a particularly higher contribution to H (T). These findings suggest that V. eizanensis had been isolated in two large glacial refugia, whereas populations of V. chaerophylloides var. sieboldiana were restricted to a single small refuge. Different light requirements between these two closely related species probably caused these differing responses to climatic change during the last ice age.

Lithocarpus vuquangensis (Fagaceae), a new species from Vu Quang National Park, Vietnam.

Lithocarpus vuquangensis Ngoc & Hung is described from Vu Quang National Park, North Central Vietnam. The morphological comparison and phylogenetic analysis based on rbcL, matK and ITS provided evidence that the new species was not assignable to any of the previously known taxa in Vietnam and its surrounding countries. The description, photographs, preliminary conservation status and DNA barcode sequences are also provided for the new species.

A taxonomic study of Quercus langbianensis complex based on morphology and DNA barcodes of classic and next generation sequences.

The taxonomy of Quercus langbianensis and its relatives in Vietnam and Cambodia have been revised based on evidence obtained from field observations, morphological comparison of herbarium specimens and molecular analyses using both classic and next generation DNA markers. Based on Bayesian inference using rbcL, matK and ITS regions and Neighbour-joining tree using genome-wide sequences amplified with multiplexed inter-simple sequence repeat (ISSR) primers (MIG-seq), the authors recognised ten species in the complex in Vietnam and Cambodia, three of which are newly described in this paper: Q. baolamensissp. nov., Q. bidoupensissp. nov. and Q. honbaensissp. nov. These new species are all phenotypically similar to Q. langbianensiss. str. in having lanceolate to oblanceolate leaf shape, upper 4-5/6-serrated leaf margin, acute or acuminate leaf apex and bracts of cupule arranged in 5-9 rings but distinguished both morphologically and phylogenetically. In molecular phylogenetic reconstructions, Q. bidoupensis is not close to any other species. In the Bayesian tree, Q. honbaensis is sister to both Q. blaoensis and Q. camusiae that are found in the same locality but morphologically distinct and those three species are sister to Q. langbianensiss. str., while Quercus baolamensis is not sister to Q. langbianensiss. str. in both the Bayesian tree and MIG-seq tree. In addition, Q. cambodiensis and Q. baniensis previously reduced to Q. langbianensiss. lat. have been recognised as distinct species. Six species were in need of lectotypification and that is undertaken herein.

Garcinia hopii (Clusiaceae), a new species from Bidoup Nui Ba National Park, southern Vietnam.

A new species, Garcinia hopii H.Toyama & V.S.Dang is described from Bidoup Nui Ba National Park, southern Vietnam. This species is similar to Garcinia hendersoniana Whitmore but differs from that species in having larger leaves, clustered pistillate flowers, a greater number of sterile anthers and a larger stigma of young fruits. A description, preliminary conservation assessment, illustration, photographs and DNA barcodes of the new species are provided, as well as an updated key to Garcinia sect. Hebradendron in Indochina.

Macrosolen bidoupensis (Loranthaceae), a new species from Bidoup Nui Ba National Park, southern Vietnam.

Macrosolen bidoupensis Tagane & V.S.Dang, sp. nov. (Loranthaceae) is newly described from Bidoup Nui Ba National Park in Lam Dong Province, southern Vietnam. The new species is characterized by small broadly elliptic to circular leaves, sessile to short petioles, slightly cordate to rounded leaf bases, 4-5 pairs of lateral veins and a basally green corolla tube. An illustration, a summary of DNA barcoding of the plastid genes rbcL and matK, and a key to the species of Macrosolen in Vietnam are provided.

Flora of Bokor National Park V: Two new species of Machilus (Lauraceae), M. bokorensis and M. brevipaniculata.

Two new species, Machilus bokorensis Yahara & Tagane and Machilus brevipaniculata Yahara & Tagane (Lauraceae) are described from Bokor National Park, Cambodia with their illustrations and DNA barcodes of the two plastid regions of rbcL and matK and the nuclear region of ITS.

A new species of Eustigma (Hamamelidaceae) from Hon Ba Nature Reserve, Vietnam.

A new species of Hamamelidaceae, Eustigma honbaense H.Toyama, Tagane & V.S.Dang, sp. nov., is described from Hon Ba Nature Reserve, Vietnam. This species is similar to Eustigma oblongifolium Gardner & Champ., but differs from it in having entire leaves, longer infructescences, capsules with a longer apical part and seeds with a larger hilum. A description, preliminary conservation assessment, illustration and photographs of the new species are provided, as well as an updated key to the genus Eustigma.

Popowia bachmaensis (Annonaceae), a new species from Bach Ma National Park, Central Vietnam.

A new species, Popowia bachmaensis Ngoc, Tagane & Yahara, sp. nov. is described from Bach Ma National Park in Thua Thien Hue Province, Central Vietnam. This species is morphologically similar to Popowia pisocarpa (Blume) Endl. ex Walp., but can be readily distinguished from it by its lower stems, smaller leaves, shorter flowering pedicels, shorter carpels, longer sepals and inner petals. A detailed description, comprising illustrations, and supplemented with DNA barcodes of the two regions of rbcL and matK, are provided.

Homalium glandulosum (Salicaceae), a new species from Vu Quang National Park, North Central Vietnam.

Homalium glandulosum Tagane & V. H. Nguyen, from Vu Quang National Park in northern Vietnam, is newly described. This species is characterized by distinct glands, often stalked, at the base of the lamina and along the margin of the stipules and bracteoles. Illustrations, DNA barcodes of the two regions of rbcL and matK, and a key to the species of Homalium in Vietnam are also provided.

Goniothalamusflagellistylus Tagane & V. S. Dang (Annonaceae), a new species from Mt. Hon Ba, Vietnam.

A new species, Goniothalamusflagellistylus Tagane & V. S. Dang, sp. nov. from Hon Ba Nature Reserve in Khanh Hoa Province, South Vietnam is described and illustrated. This species is most similar to Goniothalamustortilipetalus M.R.Hend., but distinct in having 308-336 stamens (vs. ca. 170-260) and ca.120 carpels (vs. ca. 50-100) per flower, and Stigma and pseudostyles ca.8.5 mm (vs. 4-4.5 mm) long.

Aporosa tetragona Tagane & V. S. Dang (Phyllanthaceae), a new species from Mt. Hon Ba, Vietnam.

A new species, Aporosa tetragona Tagane & V. S. Dang, sp. nov., is described and illustrated from Mt. Hon Ba located in the Khanh Hoa Province, South Vietnam. This species is characterized by tetragonal pistillate flowers and fruits, which are clearly distinguishable from the other previously known species of the genus. The morphology and phylogeny based on rbcL and matK of this species indicated that the new species belongs to section Appendiculatae Pax & K. Hoffm.

Effects of logging and recruitment on community phylogenetic structure in 32 permanent forest plots of Kampong Thom, Cambodia.

Ecological communities including tropical rainforest are rapidly changing under various disturbances caused by increasing human activities. Recently in Cambodia, illegal logging and clear-felling for agriculture have been increasing. Here, we study the effects of logging, mortality and recruitment of plot trees on phylogenetic community structure in 32 plots in Kampong Thom, Cambodia. Each plot was 0.25 ha; 28 plots were established in primary evergreen forests and four were established in secondary dry deciduous forests. Measurements were made in 1998, 2000, 2004 and 2010, and logging, recruitment and mortality of each tree were recorded. We estimated phylogeny using rbcL and matK gene sequences and quantified phylogenetic α and ß diversity. Within communities, logging decreased phylogenetic diversity, and increased overall phylogenetic clustering and terminal phylogenetic evenness. Between communities, logging increased phylogenetic similarity between evergreen and deciduous plots. On the other hand, recruitment had opposite effects both within and between communities. The observed patterns can be explained by environmental homogenization under logging. Logging is biased to particular species and larger diameter at breast height, and forest patrol has been effective in decreasing logging.