Eun-Kyeong Han

Damnacanthus indicus C. F. Gaertn. and D. major Siebold & Zucc. are taxonomically complex species with extensive morphological variation and polyploidy. To provide molecular tools for future taxonomic and population genetic studies of the polyploid D. indicus–D. major species complex, we assessed ploidy levels based on nuclear DNA content using flow cytometry and developed 25 polymorphic microsatellite markers. Flow cytometric analysis showed an approximately twofold difference in nuclear DNA content between diploid and tetraploid individuals, consistent with their reported chromosome numbers. Genotyping of 60 individuals representing diploid D. indicus, tetraploid D. indicus, and tetraploid D. major revealed substantial polymorphism, with expected (HE) and observed (HO) heterozygosity ranging from 0–0.812 and 0–0.917, 0.348–0.815 and 0.250–0.962, and 0–0.757 and 0–0.987, respectively. The developed markers will serve as valuable tools for future taxonomic reexaminations and for investigating the evolutionary processes that have shaped the D. indicus–D. major species complex.

The temperate woody bamboos (tribe Arundinarieae) present long-standing taxonomic uncertainty owing to rapid radiation, frequent hybridization, and convergent morphology, which obscure species-level relationships. Although plastome phylogenomics has clarified deep lineages at the species level, Korean and Japanese taxa have received little molecular attention, leaving East Asian species diversity incompletely understood. To address this gap, we analyzed plastid genome data from 36 species and nuclear ribosomal ITS (nrITS) data from 30 species. We newly assembled complete plastomes for 12 species, seven of which are reported here for the first time. The plastome phylogeny recovered two strongly supported lineages, the Arundinaria and Phyllostachys clades, consistent with earlier studies. By contrast, the nrITS phylogeny showed substantial topological incongruence, revealing plastid-nuclear discordance with the plastome tree, particularly in the placement of the Pleioblastus subclade. Nevertheless, many species were consistently resolved within the same clades or subclades across both datasets, indicating stability at lower phylogenetic levels. Seven taxa, however, exhibited conflicting placements, suggesting signals of hybrid origin. A notable case was Arundinaria munsuensis, a Korean endemic restricted to Mt. Jirisan, which was consistently resolved within Pleioblastus in both plastome and nrITS phylogenies, supported also by morphological evidence. We therefore propose the new combination Pleioblastus munsuensis (Y. N. Lee) A. Gantsetseg, Y. J. Jang, E. K. Han & J. H. Lee. Taken together, these findings highlight plastid-nuclear conflict in Arundinarieae, with hybridization likely contributing to phylogenetic instability, and indicate that certain taxa remain in need of species-level taxonomic re-evaluation, either due to hybrid origins or to nomenclatural uncertainty.

Hepatica insularis, a warm-temperate endemic confined to the southwestern coastal region and Jeju Island of Korea, has long posed a taxonomic challenge in relation to Hepatica asiatica, which is more broadly distributed across cool-temperate regions of northeastern Asia. To address this issue, we investigated their phylogeographical history. Genetic analyses were conducted using eight nuclear microsatellite loci and three non-coding regions of plastid DNA, based on 294 individuals sampled from 13 populations across the Korean Peninsula. Analyses of nuclear markers revealed two distinct genetic clusters concordant with geographical distribution, whereas plastid variation revealed a contrasting signal suggestive of incomplete lineage sorting (ILS). Our demographic analyses estimated that H. insularis and H. asiatica diverged approximately 17 200 years ago around the Last Glacial Maximum (LGM). The current nuclear structure probably reflects historical separation of humid coastal refugia situated along the palaeo-coastlines of the Korean Peninsula and the exposed East China Sea shelf during the LGM. Given the recency of divergence, which has resulted in ILS, we propose that these taxa do not represent distinct species, but instead reflect population-level divergence within a single species. This study sheds light on how rapid evolutionary radiation unfolds in Hepatica species and its implications for their taxonomic interpretation.

Daphne pseudomezereum var. koreana has traditionally been treated as a variety of D. pseudomezereum, a species endemic to the warm-temperate regions of Japan. However, var. koreana occurs primarily in cool-temperate regions of northeastern Asia— including the Baekdudaegan Mountain Range in Korea, southern Manchuria, southern Primorsky Krai, Sakhalin, and Hokkaido—and thus exhibits distinct ecological and biogeographic characteristics from var. pseudomezereum. To reassess its taxonomic position, we conducted molecular phylogenetic analyses using complete chloroplast genome and nuclear ribosomal ITS sequences. Plastome phylogeny supports var. koreana as a sister to D. kamtschatica, whereas nuclear ribosomal internal transcribed spacer phylogeny places it as a sister to var. pseudomezereum. While the phylogenetic discordance complicates its placement, we interpret this discordance as in itself ultimately revealing var. koreana as a lineage bearing an evolutionary identity possibly shaped by ancient hybridization. Evidence from ecology, biogeography, life-history (presence of well-developed rhizomes), and morphology (e.g., growth habit, calyx coloration, anther position) further supports its affinity with D. kamtschatica. Taken together, we propose reclassifying var. koreana as a variety of D. kamtschatica, representing a geographically disjunct southwestern lineage separated from var. kamtschatica by the Sea of Okhotsk. Plants occurring in southern Japan currently considered to be var. koreana may instead represent distinct, undescribed taxa.

Hepatica insularis Nakai, a perennial herb endemic to warm-temperate regions on the Korean Peninsula, has been a subject of taxonomic debate due to its morphological similarities with Hepatica asiatica Nakai. To address the taxonomic ambiguity and provide evolutionary insights into H. insularis, we developed 15 polymorphic microsatellite markers. Of these, eight markers were successfully cross-amplified in H. asiatica, demonstrating their broader applicability. The markers exhibited high levels of polymorphism, with the number of alleles per locus ranging from two to eleven. The expected heterozygosity (HE) and observed heterozygosity (HO) values ranged from 0.180 to 0.802 and from 0.000 to 0.933, respectively. The developed markers will serve as a valuable tool for future phylogeographic studies aiming to understand the genetic structure and diversity of H. insularis and related taxa.

Quercus turbinella (section Quercus; Fagaceae) is an evergreen shrub characteristic in central Arizona and it concerns one of the most abundant and economically important genera of Quercus in the Northern Hemisphere. Here, we have sequenced the complete chloroplast genome to provide insight into the phylogenetic relationship of Q. turbinella. The whole genome is 161,208 bp in length with two inverted repeat regions of 25,827 bp each, which separate a large single-copy region of 90,552 bp and a small single-copy region of 19,002 bp. A total of 136 genes were annotated, including 88 protein-coding genes, eight ribosomal RNAs, and 40 transfer RNAs. The result of the maximum-likelihood phylogenetic analysis strongly suggested that Quercus turbinella had a close relationship to Quercus macrocarpa with strong bootstrap support.

1. Twigs and rachis of infructescence rather stout; leaves ovate-oblong or oblong, apex acuminate or long acuminate; cupule without tubercles; nut ovoid-elliptic or ovoidoblong, 1.2–2.1 cm (length/width = 1.4–2.2) ···················· ············································································ C. sieboldii

Unnoticed and silently, a certain midge has emerged that could pose a threat to the evergreen forests on the Korean Peninsula and the associated island ecosystems. We report the discovery of an unrecorded species on the Korean Peninsula, identified as Schizomyia castanopsisae Elsayed & Tokuda, 2018 (Diptera: Cecidomyiidae). This previously unrecorded gall midge species induces galls on a reproductive organ of Castanopsis sieboldii, specifically the inflorescences, and was found in the natural monument forest on Yokjido Island. A total of 40 larvae were collected from 8 inflorescence galls, each obtained from individual hosts within the forest. Morphological examinations and mitochondrial DNA cytochrome oxidase subunit I (COI) region sequencing were conducted for each specimen, confirming the identification of the gall inducer as S. castanopsisae. The COI sequences from the 40 specimens collected on Yokjido Island were identical, showing a 99.8% match with individuals from Kyushu, Japan. Additionally, a maximum likelihood tree analysis revealed a sister relationship between Yokjido Island and Kyushu individuals. Considering the tropical nature of gall midge species, it suggests recent northward migration from Kyushu to Yokjido Island. This species not only significantly reduces acorn production but also has the potential to negatively impact organisms associated with acorns. Drawing from cases in Japan, this species has the potential to rapidly dominate evergreen broad-leaved forests on numerous islands in the Korean Peninsula. Therefore, urgent additional research on aspects such as natural enemies of this species, its dispersal mechanisms, and other relevant factors is necessary. We also investigated the distribution of trees with inflorescences gall-induced by S. castanopsisae in the Yokjido Island Natural Monument Forest. The occurrence frequency of these galls is estimated to be approximately 10 percent.

Similar to the global phenomenon, many plant species endemic to Korean limestone karst forests are at risk of extinction due to human intervention. Zabelia tyaihyonii is a familiar shrub, called “Hardy abelia” and “Fragrant abelia” growing in the karst forests of Korea, where it is one of the most threatened species. We investigated the genetic structure and demographic history of Z. tyaihyonii, which allow us to develop appropriate conservation and management strategies. The genetic structure was evaluated using a total of 187 samples from 14 populations, covering the entire distribution of Z. tyaihyonii in South Korea. We utilized 254 and 1753 SNP loci obtained via MIG‐seq (Multiplexed ISSR Genotyping by sequencing) for structure and demographic analyses, respectively. The population demographic modeling was performed with site frequency spectrum. To gain further historical insights, we also employed ENM (Ecological Niche Modeling). We found two distinct clusters (CLI and CLII) of ancient origin (ca. 490 ka). Despite CLII experiencing a more severe bottleneck, both clusters showed similar levels of genetic diversity, indicating mutual historical gene flow. Their historical distribution range seems to have changed very little. We proposed a historical distribution scenario for Z. tyaihyonii, taking into account its intrinsic factors, and emphasized a more complex response to Quaternary climate change beyond simple allopatric speciation models. These findings provide valuable insights for conservation and management strategies for Z. tyaihyonii.

Paraphlomis koreana (Lamiaceae) was newly named and added to Korean flora in 2014. Paraphlomis belongs to the tribe Paraphlomideae, along with Ajugoides and Matsumurella. However, a recent study has suggested that P. koreana is morphologically similar to Matsumurella chinensis, making them difficult to distinguish from each other. Therefore, we aimed to examine the phylogenetic placement of P. koreana within the tribe and compare its genetic relationship with M. chinensis. We sequenced an additional complete plastid genome for an individual of P. koreana and generated sequences of nuclear ribosomal (nr) DNA regions of internal and external transcribed spacers (ITS and ETS) for two individuals of P. koreana. Maximum likelihood analyses based on two nrDNA regions (ITS and ETS) and four plastid DNA markers (rpl16 intron, rpl32-trnL, rps16 intron, and trnL-F) covering 13 Paraphlomis species and M. chinensis were conducted. Phylogenetic analyses concordantly supported that P. koreana forms a monophyletic group with M. chinensis. Moreover, our study revealed that P. koreana includes nrDNA sequences of M. chinensis as minor intraindividual variants, suggesting that the genetic divergence between the two taxa is incomplete and may represent intraspecific variation rather than distinct species. In conclusion, our findings suggest that the independent species status of P. koreana within Paraphlomis should be reconsidered.