Endemic plants refer to plants that grow naturally and exclusively in a specific region, and the distribution of nationally endemic plants is limited to the territory of a country (Siljak-Yakovlev and Peruzzi, 2012; Coelho et al., 2020). Most endemic plants have restricted geographical ranges or population sizes, making them vulnerable to artificial threats and natural changes such as increasing climate change, which can lead to population decline or extinction. Therefore, endemic plants should be prioritized in conservation, and they should be managed as a global concern (Shaffer, 1981; Cahill et al., 2013; Coelho et al., 2020).

Since Nakai (1952) first compiled 1,118 taxa of endemic plants of the Korean Peninsula, subsequent studies have reported varying numbers of taxa (except forms): 387 (Lee, 1984), 465 (Paik, 1999), 340 (Kim, 2004), 326 (Oh et al., 2005), 358 (Korea Forest Service, 2012), 375 (National Institute of Biological Resources, 2013), and 59 (Park et al., 2013), and 360 (Chung et al., 2017a). However, subsequent studies (e.g., Gil et al., 2019; Sun et al., 2020), have revealed that some taxa previously considered endemic to the Korean Peninsula also occur in neighboring countries such as Russia, China, and Japan, or are treated taxonomically as synonyms of related taxa. Furthermore, recent studies (e.g., Kim et al., 2018; Park et al., 2022) have reported newly identified taxa endemic to the Korean Peninsula. Despite the ongoing inclusion of taxa that should have been excluded, and of newly recorded endemic plants for the Korean Peninsula, there has been a lack of comprehensive data reflecting these changes. To address this gap, this study aimed to provide an updated list of endemic plants of the Korean Peninsula, incorporating new research since Chung et al.’s (2017a) list. This updated list serves as a basis for research and policy activities related to the conservation of endemic plants.

This study comprises a review of the list of endemic plants compiled by Chung et al. (2017a) and re-evaluation of taxa that were excluded or overlooked at the time of publication. A list was prepared by carefully reviewing relevant Korean and international journals, dissertations, monographs, and illustrated books for all taxa above the rank of variety newly described as endemic to the Korean Peninsula from late 2016 to 2022.

The following criteria for selecting plants endemic to the Korean Peninsula were applied. First, plants distributed exclusively on the Korean Peninsula were identified. The revised checklist excludes taxa revealed by objective published data to be native to countries neighboring the Korean Peninsula, such as China, Russia, and Japan; such cases were reviewed by Korean taxon experts. Second, taxa formally treated by Korean or foreign taxonomists as heterotypic synonymous of another taxa of above the rank of variety, based on specimens collected on the Korean Peninsula, were excluded. However, taxa mentioned as synonymous, but without supporting evidence such as specimen records, were included as endemics unless the Korean experts disagreed. Third, currently recognized forms were excluded whereas natural hybrids were included. Fourth, following the International Code of Nomenclature for Algae, Fungi, and Plants (ICN, Turland et al., 2018), taxa with not validly published or illegitimate names were excluded, regardless of the taxon’s validity.

The resulting list of Korean endemic plants was then arranged in the order of ferns, gymnosperms, and angiosperms (dicots and monocots). Within each group, the following classification systems were applied: for ferns, that of The Pteridophyte Phylogeny Group (PPG I, 2016); for gymnosperms, that of Christenhusz et al. (2011); and for angiosperms, those of Melchior and Werderman (1954) and Melchior (1964). Furthermore, within families and genera, the taxa were generally arranged in alphabetical order. The scientific names and Korean names of the taxa follow the National Standard Plant List (Korean Plant Names Index Committee, 2023) based on the “Act on the Management of Arboretums, Gardens, and Promotion of their Use.” For angiosperms, if the family name differed when the Angiosperm Phylogeny Group IV system (APG IV, 2016) was applied at status below that of genus, this is indicated in parentheses (Appendix 1).

Considering the discovery of new taxa and frequent revisions in accepted names through taxonomic researches, the identification of Korean endemic plants, an indigenous Korean resource, is highly important for strengthening biological sovereignty. Moreover, an accurate list of endemic plants is a prerequisite for establishing conservation policies that must be implemented despite the limited resources available.

This study identified 373 Korean endemic taxa, comprising 64 families, 179 genera, 304 species, six subspecies, 49 varieties, and 14 hybrids. This corresponds to 9.5% of the 3,939 taxa native to the Korean Peninsula (Korean Plant Names Index Committee, 2023). Of the 373 endemics, 11 are ferns, three are gymnosperms, and of the angiosperms, 293 are dicots, and 66 are monocots (Appendix 1). Asteraceae is the most common family (41 taxa), followed by Apiaceae (29 taxa), Liliaceae (24 taxa), and Rosaceae (22 taxa). Six Korean endemic genera were included: Mankyua B. Y. Sun, M. H. Kim & C. H. Kim, Abeliophyllum Nakai, Coreanomecon Nakai, Hanabusaya Nakai, Megaleranthis Ohwi, and Sillaphyton Pimenov.

Compared with the recent study by Chung et al. (2017a), 39 taxa have now been excluded: Aster magnus Y. N. Lee & C. S. Kim, based on its invalid name; seven taxa with additional distributions in countries neighboring the Korean Peninsula (including Salix koriyanagi Kimura ex Goerz and Corydalis humilis B. U. Oh & Y. S. Kim); four taxa ranked as form [including Berberis koreana Palib. f. angustifolia (Nakai) W. T. Lee]; and 27 taxa, based on their synonymy with taxa distributed beyond the Korean Peninsula [including Arabis columnaris Nakai and Ligularia fischeri (Ledeb.) Turcz. var. spiciformis Nakai] (Tables 1–4).

Among the list presented by Chung et al. (2017a), four taxa were recognized with their taxonomic identity, but their scientific names were not validly published or illegitimate according to ICN. Additionally, misapplications and errors in nomenclature were identified. As a result, the scientific names were corrected to reflect the latest research and included in the revised list. Asplenium ×bimixtum C. S. Lee & K. H. Lee ex Y.-H. Ha is a recognized taxonomic entity, but its original scientific name, Asplenium ×montanus C. S. Lee & K. H. Lee was published under an illegitimate name as a later homonym. Furthermore, the replacement name proposed by Lee and Lee (2018) was also not usable. The citation referenced all of the pages in the source, instead of specifically mentioning the page number of the protologue, thereby rendering it ultimately not validly published (Ha et al., 2020). Aster danyangensis J. Y. Kim & G. Y. Chung was erroneously given the valid name Aster uchiyamai Nakai, based on the its mistaken treatment as a heterotypic synonym of Aster meyendorffii (Regel & Maack) Voss due to the similarity of their specific epithets. Kim et al. (2022b) therefore published a new name for this taxon. Vicia anguste-pinnata Nakai, despite the fact that, under the ICN rules, only a legitimate name has priority, and when multiple legitimate names are published simultaneously within the same rank, the first validly published selected name should take precedence. However, an amendment was made to rectify this selection error (Kwon and Choi, 2001) and apply the corrected scientific name (Table 6).

Before publication of the checklist by Chung et al. (2017a), 10 taxa, including Alnus incana (L.) Moench subsp. tchangbokii Chin S. Chang & H. Kim and Carex nakasimae Ohwi, were recognized as Korean endemics. An additional 42 taxa have been identified since the publication of Chung et al. (2017a). Most of these were newly discovered or endemic taxa identified by Korean researchers. However, various taxa, including Tsuga ulleungensis G. P. Holman, Del Tredici, Havill, N. S. Lee & C. S. Campb., Clematis urticifolia Nakai ex Kitag., Salix cacuminis A. K. Skvortsov, Chamaelirium japonica (Willd.) N.Tanaka subsp. yakusimense (Masam.) N. Tanaka var. koreanum (F. T. Wang & T. Tang) N. Tanaka, Acer takesimense Nakai, Potentilla squamosa Soják, and Festuca ovina L. var. chiisanensis Ohwi, have been recognized as Korean endemics by foreign researchers (Table 5).

The perception of endemic plants can vary depending on the comprehensive research findings for each taxon. As illustrated here, over the past five years, 52 taxa have been newly reported or identified as Korean endemics, while 27 are no longer considered endemics following taxonomic revision based on systematic studies. It is therefore necessary to periodically revise the list of endemic plants to incorporate the latest research results. Not only are Korean endemic plants important for understanding the formation of the Korean flora and identifying the phylogenetic and geographical origins of major taxa, they also represent our unique plant heritage, and their conservation should be considered a top priority in terms of protecting Korean biological sovereignty. Recognizing the significance of conserving endemic plants plays a vital national role. This revised checklist is expected to contribute greatly to a clear understanding of the endemic plants of the Korean Peninsula.