Panax vietnamensis var. vietnamensis (PVV) and Panax vietnamensis var. fuscidiscus (PVF) both belong to Panax vietnamensis species and are chemically and morphologically similar, making it hard to distinguish for the consumer. Herein, 42 PVF and 12 PVV samples were collected in Quang Nam and Lai Chau Province, respectively, and subsequently characterized by ITSr-DNA sequence data to verify their origins. Next, untargeted metabolomics combined with multivariate statistical analysis was developed to differentiate PVV and PVF. The metabolic profiles of PVV and PVF were found to be distinct and classified well using Partial Least-Squares Discriminant Analysis (PLS-DA) in the training set. Among them, seven ginsenosides were of high abundance in PVV, while six were of high abundance in PVF. Next, the test set was used to validate 13 putative differential markers found in the training set, illustrating a complete match with the expression patterns of these ginsenosides in the training set. Finally, PLS-DA and linear Support Vector Machine models both indicated distinct ginsenoside profiles of PVV and PVF without misclassification in the test set. Conclusively, the developed untargeted metabolomics approach might serve as a powerful tool for the authentication of PVV and PVF at the metabolome level.

The endangered Dipterocarpus dyeri is distributed in forests of southeast Vietnam, which is expected to have low genetic diversity and high genetic population structure due to habitat loss and over-exploitation. To provide valuable information for conservation measures, nine polymorphic microsatellites were used to analyze 151 adult trees from six populations, representing the natural range of D. dyeri in Vietnam. Contrary to the expectation, this species has relatively high genetic diversity within populations, low genetic differentiation among populations, and suggesting high gene flow. Results of bottleneck tests showed evidence of a bottleneck in the TaKou population. Analysis of molecular variance showed a high genetic variation within populations compared to among populations. Bayesian analysis also indicated two genetic lineages related to geographical distances. These results highlight the importance of conserving the genetic resources of D. dyeri and will provide guidelines for species conservation in Vietnam.

Aristolochia luudamcui (Aristolochia subgen. Siphisia, Aristolochiaceae), a new species from Vietnam, previously misidentified as A. utriformis, is described and illustrated here. The new species is most similar to A. pseudoutriformis and A. utriformis concerning the morphology of the leaf lamina, the color of the perianth, and the shape of the limb, but A. luudamcui can be distinguished from the other two species by having a deeply 3-lobed limb and a glabrous, yellow inner surface of limb lobes. A detailed description, information on ecology, phenology, distribution, usage, a provisional assessment of the conservation status of the new species, and a comparison with morphologically similar species are provided as well.

Panax vietnamensis Ha et Grushv. is a precious medicinal species native to the tropical forests of Vietnam. Due to habitat loss and over-harvesting, this species is endangered in Vietnam. To conserve the species, we investigated genetic variability and population structure using nine microsatellites for 148 individuals from seven populations across the current distribution range of P. vietnamensis in Vietnam. We determined a moderate genetic diversity within populations (H_O = 0.367, H_E = 0.437) and relatively low population differentiation (the Weir and Cockerham index of 0.172 and the Hedrick index of 0.254) and showed significant differentiation (P < 0.05), which suggested fragmented habitats, over-utilization and over-harvesting of P. vietnamensis. Different clustering methods revealed that individuals were grouped into two major clusters, which were associated with gene flow across the geographical range of P. vietnamensis. This study also detected that ginseng populations can have undergone a recent bottleneck. We recommend measures in future P. vietnamensis conservation and breeding programs.

Aspidistra thuongiana is described and illustrated as a new species from the South Central Coast region of Vietnam. The new species has bright yellow flower and a slender pistil with a minute stigma. It is morphologically close to A. longipedunculata, but differs in shorter peduncle, bowl-shaped (vs. campanulate) perigone, shorter ovate (vs. oblong) erect to spreading (vs. recurved) perigone lobes and stamens inserted at the base (vs. middle) of perigone tube. Data on nuclear 5S-NTS region of the new species are provided, aimed to serve as a molecular characterization for comparison with its congeners.

Amentotaxus argotaenia (Hance) Pilg. is a threatened conifer with a wide distribution range from North to Central Vietnam due to habitat loss and over-exploitation. To provide information for its conservation and sustainable management, in the present study, genetic diversity and population genetic structure for 200 trees from eight populations, representing the natural distribution range of this species were estimated using nuclear microsatellites. The results showed a moderate genetic diversity of A. argotaenia (H_O = 0.331, H_E = 0.358). Significant heterozygosity deficits were detected in three populations in the Northeast area. Genetic differentiation was low in the same distribution area and high in different areas. However, the gene flow among the studied populations was relatively high (N_m = 1.17). Habitat fragmentation, geographical distance and high mountain range can be the major factors that reduce gene exchange between different areas. Various clustering analyses distinguished three major genetic groups related to the three distribution areas of this species in Vietnam. Based on the study results, we propose that some populations could be prioritized for in situ conservation due to their high genetic diversity with high allelic richness or private alleles, meanwhile other populations should be collected for ex situ conservation as genetic resources in the future.