Jian-Wen Shao

Primula pingwuensis sp. nov ., a new species of Primula sect. Auganthus from Sichuan, China, is described. It resembles P. sinensis in having palmately lobed leaves and multi-whorled inflorescences but differs by its multi-branched stems, more densely short-pubescent surfaces, thicker chartaceous leaves, narrower leaf blades, and indistinct translucent nectar guides. A taxonomic key covering all nine known species of Primula sect. Auganthus is compiled herein to support field morphological discrimination. A chloroplast genome-based phylogeny shows that P. pingwuensis is sister to P. rongrong , and this clade is sister to P. fujiangensis . Incongruence between morphology and molecular phylogeny is observed within the section. Leaf-lobing patterns have undergone multiple independent evolutionary transitions during adaptive radiation in karst habitats, indicating that a few morphological traits cannot be used to reliably infer interspecific relationships. The new species is assessed as Data Deficient (DD) following IUCN criteria, owing to the lack of long-term observations of its threat status and population dynamics. This study provides new data for the taxonomy and evolution of Primula sect. Auganthus .

Phoebe chekiangensis is a rare nanmu species endemic to southeastern China that provides high-quality timber and has ecological and economic importance. Genomic resources for this genus are limited, constraining research on its genetic diversity, adaptive evolution, and conservation. Here we report a chromosome-level reference genome of P. chekiangensis generated using PacBio HiFi long reads, MGI short reads, and Hi-C sequencing. The assembled genome spans 918.59 Mb with a scaffold N50 of 68.99 Mb, and 98.88% of sequences were anchored to 12 pseudochromosomes. Repetitive elements account for 49.45% of the genome. A total of 34,381 protein-coding genes were predicted, of which 91.91% were functionally annotated. Genome quality was supported by a QV of 44.96 (99.99% base accuracy), a BUSCO completeness of 98.4%, and an LAI score of 14.32, meeting reference-quality standards. This high-quality genome provides a valuable resource for conservation genomics, evolutionary biology, and molecular breeding within Phoebe and the Lauraceae family.

Floral orientation as a key floral trait for understanding how plants integrate biotic and abiotic selective pressures. Polygonatum cyrtonema is an economically significant medicinal species. The adaptive significance of its downward floral orientation remains poorly understood. We conducted manipulation experiments to explore the visiting time per flower, visitation rate and the pollination efficiency of bumble bees and honey bees between downward flowers and artificially reoriented upward flowers. We also assessed pollen viability and stigma receptivity under both sunlight and rainwater exposure in the two orientations. Furthermore, we quantified reproductive fitness components to compare the fruit set, seed set, and the qualities of fruit/seed between two orientation flowers. Our results showed that the downward orientation enhances reproductive success through integrated biotic and abiotic factors. Downward flowers attracted more effective bumble bee pollinators, resulting in higher visitation rates, longer visiting time, and higher pollen transfer efficiency compared to upward flowers. While the upward floral orientation increased the visitation of ineffective visitors, such as honey bees and other syrphid flies. Simultaneously, the downward orientation flowers provided protection from solar radiation and rainwater, maintaining higher pollen viability, and stigma receptivity while reducing pollen loss. Although the fruit set per plant showed no significant difference between orientations, downward flowers developed significantly larger fruits with greater fresh mass and fruit size. Both the seed number and the seed set per fruit were significantly higher in downward flowers than upward ones. These results collectively support the pollinator attraction, pollinator filtering and abiotic protection hypothesis, demonstrating that the downward orientation in P. cyrtonema is shaped by both biotic and abiotic selection.

Mountainous regions often serve as critical biodiversity hotspots. In mid-altitude mountains, populations may be more vulnerable to climate-driven fluctuations than those in alpine regions due to limited capacity for elevational range shifts. However, empirical studies on how past climatic changes shaped the demographic history of organisms in the mid-mountains remain scarce, particularly those utilizing genomic data. Here, we conducted population genomic analyses of Rhododendron shanii , an endemic species in the Dabie Mountains of eastern Asia. Combined with species distribution modeling, our demographic analyses indicate that this species underwent glacial expansion during Quaternary cooling periods but experienced three distinct population bottlenecks over the past 0.4 million years, all coinciding with interglacial warm periods. Its population size has continuously declined throughout the Holocene as temperatures rose. Significant genetic differentiation has occurred among populations inhabiting different mountaintops despite their highly restricted distribution. Notably, warm conditions during the last interglacial period (0.12–0.13 Mya) triggered the divergence between the southern lineage (S: TJ, SBG, DZJ) and the northern lineage (N: THJ, BMJ, DYJ). Compared to closely related species, R. shanii currently exhibits a high inbreeding rate yet maintains relatively high genetic diversity and low genetic load. This unique genetic signature is likely linked to its recent rapid population contraction. Collectively, our findings demonstrate how Quaternary climatic oscillations and mid-mountain topography shaped the demographic trajectories and genomic landscape of R. shanii , providing new insights into the formation and vulnerability factors of biodiversity within mid-elevation sky island systems under global warming scenarios.

Utricularia damingshanensis (Lentibulariaceae), a new species from Guangxi, China, is described and illustrated. It resembles U. caerulea and U. warburgii but differs in having a corolla palate with four hooked processes on the distal margin; lower calyx lobe distinctly shorter than the upper; distinctly striped corolla with 8–15 deep violet lines on the lower lip and 6–9 radiating lines on the upper lip, as well as a helmet-like swelling at the base of the lower lip. Phylogenetic analysis based on nrITS, rps16, and trnD–trnT strongly supported its placement in sect. Nigrescentes as sister to U. warburgii. Both morphological and molecular evidence support its status as a new species.

A new species of Ranunculaceae, Ranunculus yuexiensis , is described and illustrated from the Dabie mountains, China. R . yuexiensis is similar to R . ternatus in having root tubers. However, it can be readily distinguished from R . ternatus by its simple and fewer basal leaves, larger flower size, long petioles on the lower stem leaves, and puberulent (vs. glabrous) carpels and achenes. The complete plastomes of this new species are 155,537–156,009 bp in length and exhibit a typical quadripartite structure. Phylogenetic analysis, based on plastome data, shows that R . yuexiensis is closely related to R . ternatus , which is consistent with our morphological analysis.

The Polygonati Rhizoma have generated significant market attention for their medicinal and culinary applications. However, morphological similarities and ambiguous species boundaries complicate the identification of genera and species, thereby impeding product development and utilization within Polygonatum sensu lato. Despite the widespread application of the chloroplast genome for taxonomic boundary revisions for Polygonatum s.l., a critical gap persist regarding their genomic applicability and the lack of standardized pipelines for developing species-specific molecular markers capable of rapid discrimination among species. This study aims to assess the effectiveness of chloroplast genomes in clarifying the current taxonomic status of the genera and species of Polygonatum s.l., and develop a reliable process for rapid identification of designated species from other species. A total of 21 chloroplast genomes were sequenced and assembled, and subsequent analyses included phylogenetic inference, multiple molecular species delimitation methods, and an automated screening framework were employed for subsequent analysis. Comparative analyses revealed relatively conserved chloroplast genomes, with notable variation limited primarily to the length of IR and LSC regions. By integrating multiple delimitation methods, the chloroplast genome validated 82.46% of the current classifications of Polygonatum s.l., demonstrating strong support (90.63%) for species represented by multiple sequences, yet only moderate support (70%) for those with single-sequence representation. Additionally, this study established and validated a scalable molecular marker development framework, spanning from identification of species-specific SNPs/InDels to the design of high-resolution molecular markers, illustrated through case studies involving Heteropolygonatum and three medicinally significant Polygonatum species.

In groups undergoing rapid radiations, species delimitation among phylogenetically close sister lineages has long been a challenge. During plant surveys in northwestern Sichuan, we unexpectedly discovered two putative new species of Primula that are morphologically similar yet distinct from each other. These species resemble P. xingshanensis, which has been assigned to sect. Auganthus based on morphological characters. To clarify the precise phylogenetic positions of the two putative new species and P. xingshanensis, we sampled related taxa and conducted phylogenetic analyses using chloroplast genomes and nuclear SNPs. The results showed that the two putative new species form sister clades and are closely related to P. sinensis, while P. xingshanensis is sister to P. rupestris. All belong to the sect. Auganthus. Based on population genetic structure, morphological statistics, and artificial hybridization experiments, both putative new species should be accepted as distinct species, herein formally described as P. rongrong sp. nov. and P. fujiangensis sp. nov. Based on our field surveys and in accordance with the IUCN criteria, we assess the conservation status of P. rongrong as least concern (LC) and P. fujiangensis as critically endangered (CR).