The genus Orostachys contains a single section (sect. Orostachys), which is subdivided into two subsections based on the presence or absence of spinose appendages at the leaf apex: subsect. Appendiculatae and subsect. Orostachys. Although numerous taxonomic studies have consistently raised questions regarding generic delimitation given that the two subsections do not form a monophyletic group, recent phylogenomic studies using complete chloroplast genome sequences and Angiosperms353 technology have provided strong evidence that these two subsections should be treated as separate genera. Therefore, in this study, we describe a new genus, Spinella H.-R. Lee & K.-S. Cheon, to accommodate taxa previously placed in Orostachys subsect. Appendiculatae. In accordance with the International Code of Nomenclature for algae, fungi, and plants (ICN), we present nine new nomenclatural combinations for taxa corresponding to this new genus and provide a key to distinguish Spinella from related genera.

Keywords: Crassulaceae; new genus; Spinella; subsect. Appendiculatae; subsect. Orostachys

INTRODUCTION

The genus Orostachys Fisch. comprises approximately 15 species of perennial succulents distributed from Central Asia to Northeast Asia (Lee and Lee, 2000; Fu et al., 2001). The genus was first described by Fischer (1809), but subsequent taxonomic treatments varied considerably, with Steudel (1821) placing it within Sedum L., de Candolle (1828) within Umbilicus DC., and Bentham & Hooker (1865) within Cotyledon Tourn. ex L. However, following the studies by Berger (1930), Borissova (1939), and Webb (1964), Orostachys is now recognized as a distinct genus (Lee et al., 2022).

The infrageneric classification of Orostachys was established by Ohba (1978), who divided the genus into two sections, sect. Orostachys Fisch. and sect. Schoenlandia H. Ohba, based on leaf morphology, stamen number, and inflorescence structure. Subsequently, sect. Schoenlandia was described as a new genus, Kungia K. T. Fu, by Fu (1988) based on differences in stamen arrangement and inflorescence morphology. Consequently, only one section (sect. Orostachys) is currently recognized within the genus, subdivided into subsect. Appendiculatae H. Ohba, with spinose appendages at the leaf apex, and subsect. Orostachys Fisch., without such appendages (Ohba, 1978).

However, various morphological and molecular phylogenetic studies (Kim and Lee, 1996; Lee and Lee, 2000; Ohba, 2003; Mayuzumi and Ohba, 2004; Gontcharova et al., 2006; Gontcharov and Gontcharova, 2009; Messerschmid et al., 2020) have consistently shown that the two subsections of Orostachys do not form a clade. Consequently, persistent questions have been raised about generic delimitation; however, these studies encountered difficulties in resolving clear generic and subsectional boundaries, as the two subsections exhibited paraphyletic or polyphyletic relationships intermixed with closely related genera, Meterostachys Nakai and Hylotelephium H. Ohba.

Recent phylogenomic studies using chloroplast genomes have proven highly effective in resolving these taxonomic problems (Lee et al., 2022; An et al., 2023). These studies revealed that taxa within each subsection form well-supported monophyletic groups, but the two subsections are polyphyletic, confirming that Orostachys cannot be maintained as a single genus. Furthermore, a recent study employing Angiosperms353 (Lee et al., 2025), currently considered the most effective approach for phylogenetic evaluation in angiosperms, provided strong evidence supporting the treatment of the two subsections as separate genera.

Phylogenomic evidence corresponds well with morphological differentiation. The consistent presence of spinose appendages at leaf apices across all members of subsect. Appendiculatae is a synapomorphic character that distinguishes this clade from subsect. Orostachys. The deep phylogenetic divergence between the two subsections, together with this distinct morphological feature and complete reproductive isolation, justifies recognition at the generic level rather than maintaining them as sections or subgenera.

Therefore, based on the results of previous studies (Lee et al., 2022; An et al., 2023; Lee et al., 2025), we describe a new genus, Spinella H .-R. Lee & K.-S. Cheon, to accommodate the taxa previously placed in Orostachys subsect. Appendiculatae, and we present new nomenclatural combinations for these taxa in accordance with the International Code of Nomenclature for algae, fungi, and plants (ICN) (Turland et al., 2018). The proposed generic name Spinella is derived as the diminutive of the Latin word ‘spina,’ based on the morphological character of spinose appendages at the leaf apex shared by all taxa included in this genus.

Meanwhile, the Korean vernacular name ‘Ba-wi-sol-sok’ (바위솔속) derives from the Korean name ‘Ba-wi-sol’ (바위솔) for O. japonica (Maxim.) A. Berger, which serves as the type species of the newly established genus Spinella. Therefore, continued use of the Korean name ‘Bawisolsok’ for Orostachys would cause considerable nomenclatural confusion. Accordingly, we propose to apply the Korean name ‘Ba-wi-sol-sok’ to the genus Spinella and to designate ‘Dung-geun-ba-wi-sol-sok’ (둥근바위솔속) for Orostachys, based on the Korean name of its type species, O. malacophylla (Pall.) Fisch.

Taxonomic Treatment

Spinella H.-R. Lee & K.-S. Cheon, gen. nov.

Korean name: ba-wi-sol-sok (바위솔속).

Type species: Spinella japonica (Maxim.) H.-R. Lee & K.-S. Cheon (Fig. 1).

Fig. 1

Morphological characteristics of Spinella japonica (Maxim.) H.-R. Lee & K.-S. Cheon. A. Natural Population. B. Habit. C. Rosette. D. Leaf. E. Inflorescence. F. Flower. G. Sepal. H. Petal. I. Fruit. J. Seed.

Diagnosis: Similar to Orostachys in having conspicuous basal rosettes and terminal racemose to paniculate inflorescences, but distinguished by the presence of distinctive spinose appendages at the leaf apex. Also similar to Meterostachys in having spinose appendages at the leaf apex, but differs in being biennial with racemose or paniculate inflorescences, whereas Meterostachys is perennial with cymose inflorescences.

Herbs, biennial, succulents. Roots fibrous to slightly thickened. Rosette leaves alternate, densely aggregated; blades lanceolate, ovate, elliptic, oblong, oblanceolate, or spatulate, apex with spinose appendage, obtuse, cuspidate or acute, margins entire, both surfaces glabrous, ± purplish spots. Stem leaves alternate; blades linear, lanceolate, ovate or spatulate, apex with spinose appendage, obtuse, cuspidate, acute, or acuminate, margins entire, both surfaces glabrous, ± purplish spots. Inflorescences terminal, racemose or paniculate, branched near base in some species (e.g., S. fimbriata); bracts linear to lanceolate, sometimes with purplish spots. Flowers pedicellate or subsessile, bisexual, actinomorphic, 5-merous; petals white, whitish-green, pale yellow, or reddish, ± red spots, lanceolate to ovate; stamens 10, arranged in two whorls; anthers yellow, pink, or purple; carpels 5, free. Fruits follicles. Seeds brown to dark brown, ovoid to oblong-ovoid.

Distribution: Taxa of this genus are distributed in the Korean Peninsula, China (Northeast, North, and Central regions), Mongolia, Russia (Far East), and Japan, occurring primarily on rocks, cliffs, and stone crevices. Depending on taxon, they grow at elevations ranging from lowland coastal areas to high mountains.

Etymology: The name Spinella reflects the most distinctive morphological feature of this genus, the spinose appendage at the leaf apex. It derives from the root “spina” (Latin: “spine, thorn, or sharp point”) with the diminutive suffix “-ella” to emphasize the consistent presence of these small, spinelike appendicular structures across all species in the genus.

Including species: Spinella cartilaginea, S. chanetii, S. fimbriata, S. japonica, S. latielliptica, S. margaritifolia, S. minuta, S. spinosa, and S. thyrsiflora.

New combinations

1. Spinella cartilaginea (Boriss.) H.-R. Lee & K.-S. Cheon, comb. nov.; Orostachys cartilaginea Boriss., Fl. URSS 9: 482, 1939.

Distribution: Russia (Far East); China (NE China) (Fu et al., 2001).

2. Spinella chanetii (H. Lév.) H.-R. Lee & K.-S. Cheon, comb. nov.; Sedum chanetii H. Lév., Repert. Spec. Nov. Regni Veg. 5: 99, 1908; Orostachys chanetii (H. Lév.) A . Berger, Nat. Pflanzenfam. 18a: 464, 1930; Sedum fimbriatum (Turcz.) Franch. var. chanetii (H. Lév.) Fröd., Acta Horti Gothoburgensis 6: 13, 1931.

Sedum pyramidale Praeger, J. Bot. 55: 42, 1917.

Distribution: China, North Korea (Fu et al., 2001).

3. Spinella fimbriata (Turcz.) H.-R. Lee & K.-S. Cheon, comb. nov.; Cotyledon fimbriata Turcz., Bull. Soc. Imp. Naturalistes Moscou 17: 241, 1844; Umbilicus fimbriatus (Turcz.) Turcz., Bull. Soc. Imp. Naturalistes Moscou 17: 241, 1844; Sedum fimbriatum (Turcz.) Franch., Nouv. Arch. Mus. Hist. Nat., sér. 2, 6: 8, 1883; Orostachys fimbriata (Turcz.) A. Berger, Nat. Pflanzenfam. 18a: 464, 1930.

Umbilicus ramosissimus Maxim., Mém. Acad. Imp. Sci. St.-Pétersbourg Divers Savans 9: 472, 1859; Sedum ramosissimum (Maxim.) Franch., Pl. David. 1: 128, 1884; Orostachys ramosissima (Maxim.) V. V. Byalt, Probl. Bot. Rubeshe 20/21: 167, 1998.

Sedum limuloides Praeger, Proc. Roy. Irish Acad. 35: 2, 1919; Orostachys fimbriata subvar. limuloides (Praeger) H. Jacobsen, Natl. Cact. Succ. J. 10: 80, 1955; Orostachys limuloides (Praeger) Jankalski, Newslett. Sedum Soc. 133: 75, 2020.

Umbilicus denticulatus Turcz. ex A. Boriss., Fl. URSS 9: 113, 1939.

Orostachys fimbriata var. grandiflora F. Z. Li & X. D. Chen, Bull. Bot. Res. Harbin 9: 73, 1989.

Orostachys fimbriata var. shandongensis F. Z. Li & X. D. Chen, Bull. Bot. Res. Harbin 9: 74, 1989.

Orostachys jiuhuaensis X. H. Guo & X. L. Liu, Bull. Bot. Res. Harbin 11: 29, 1991.

Distribution: China, North Korea, Japan (Fu et al., 2001; Ohba, 2003).

4. Spinella japonica (Maxim.) H.-R. Lee & K.-S. Cheon, comb. nov.; Cotyledon japonica Maxim., Bull. Acad. Imp. Sci. Saint-Pétersbourg sér.3, 30: 122, 1883; Sedum japonicola Makino, J. Jap. Bot. 4: 8, 1927; Orostachys japonica (Maxim.) A. Berger, Nat. Pflanzenfam. 18a: 464, 1930; Sedum malacophyllum var. japonicum (Maxim.) Fröd., Acta Horti Gothob. 6: 10, 1931; Orostachys erubescens var. japonica (Maxim.) Ohwi, Bull. Natl. Sci. Mus. Tokyo 33: 73, 1953; Sedum erubescens var. japonicum (Maxim.) Ohwi, Fl. Jap. (rev. ed.) 693, 1965.―TYPE: JAPAN. Honshu, Kanagawa Pref., Yokohama, 1862, C. J. Maximowicz s.n. (lectotype: LE [01015589], designated by Byalt, 2000, photo!) (Fig. 2).

Fig. 2

Lectotype of Spinella japonica (Maxim.) H.-R. Lee & K.-S. Cheon, the type species of Spinella (LE [01015589]).

Cotyledon polycephala Makino, Somoku Dzusetsu, ed. 3, 2: 658, 1910; Sedum polycephalum (Makino) Makino, J. Jap. Bot. 4: 8, 1927; Orostachys polycephala (Makino) H. Hara, Bot. Mag. (Tokyo) 49: 73, 1935; Orostachys erubescens var. polycephalum (Makino) Ohwi, Bull. Natl. Sci. Mus. Tokyo 33: 73, 1953; Sedum erubescens var. polycephalum (Makino) Ohwi, Fl. Jap., rev. ed.: 1440, 1965; Orostachys japonica f. polycephalus (Makino) H.Ohba, J. Jap. Bot. 56: 185, 1981; Orostachys japonica var. polycephala (Makino) Jankalski, Newslett. Sedum Soc. 133: 74, 2020.

Orostachys kanboensis Ohwi, Acta Phytotax. Geobot. 11: 249, 1942.

Distribution: Korea, Japan, China (Lee and Lee, 2000; Fu et al., 2001; Ohba, 2003).

5. Spinella latielliptica (Y. N. Lee) H .-R. Lee & K.-S. Cheon, comb. nov.; Orostachys latielliptica Y. N. Lee, Bull. Korea Pl. Res. 1: 35, 2000.

Distribution: South Korea (Lee and Lee, 2000).

6. Spinella margaritifolia (Y. N. Lee) H.-R. Lee & K.- S. Cheon, comb. nov.; Orostachys margaritifolia Y. N. Lee, Bull. Korea Pl. Res. 1: 36, 2000.

Distribution: South Korea (Lee and Lee, 2000).

7. Spinella minuta (Kom.) H.-R. Lee & K.-S. Cheon, comb. nov.; Cotyledon minuta Kom., Trudy Imp. S.- Peterburgsk. Bot. Sada 18: 436, 1901; Orostachys minuta (Kom.) A. Berger, Nat. Pflanzenfam. (Engler & Prantl), 2nd ed., 18a: 464, 1930.

Orostachys minuta f. alba Y. N. Lee, Bull. Korea Pl. Res. 1: 33, 2000.

Distribution: China, Korea, Russia (Far East) (Lee and Lee, 2000; Fu et al., 2001).

8. Spinella spinosa (L.) H.-R. Lee & K.-S. Cheon, comb. nov.; Cotyledon spinosa L., Sp. Pl. 1: 429, 1753; Crassula spinosa (L.) L., Mant. Pl. Altera 388, 1771; Sedum spinosum (L.) Thunb, Fl. Jap. 186, 1784; Umbilicus spinosus (L.) DC., Prodr. 3: 400, 1828; Orostachys spinosa (L.) C. A. Mey., Reise Altai-Geb. Kirg.-Steppe 2: 496, 1830; Orostachys spinosa (L.) C. A. Mey., Reise Altai-Geb. Kirg.-Steppe 2: 496, 1830.

Sempervivum cuspidatum Haw., Misc. Nat. 186, 1803.

Umbilicus erubescens Maxim., Mém. Acad. Imp. Sci. St.- Pétersbourg Divers Savans 9: 114, 1859; Orostachys erubescens (Maxim.) Ohwi, Acta Phytotax. Geobot. 11: 249, 1942; Sedum erubescens (Maxim.) Ohwi, Fl. Jap. (rev. ed.) 1440, 1965; Orostachys spinosa var. erubescens (Maxim.) V. V. Byalt, Turczaninowia 20: 197, 2017.

Distribution: Russia, Mongolia, China, North Korea (Fu et al., 2001).

9. Spinella thyrsiflora (Fisch.) H.-R. Lee & K.-S. Cheon, comb. nov.; Orostachys thyrsiflora Fisch., Mém. Soc. Imp. Naturalistes Moscou 2: 274, 1809; Umbilicus thyrsiflorus (Fisch.) DC., Prodr. 3: 400, 1828; Cotyledon thyrsiflora (Fisch.) D. Dietr., Syn. Pl. 2: 1627, 1840; Cotyledon spinosa var. thyrsiflora (Fisch.) Fröd., Acta Horti Gothob. 6: 15, 1931.

Cotyledon leucantha Ledeb., Fl. Altaic. 2: 198, 1830; Umbilicus leucanthus (Ledeb.) G. Don, Gen. Hist. 3: 113, 1834; Umbilicus leucanthus (Ledeb.) Ledeb., Fl. Ross. 2: 173, 1843.

Cotyledon rosea Less., Linnaea 9: 177, 1834; Orostachys rosea (Less.) A. Berger, Nat. Pflanzenfam., 2. Aufl., 18a: 464, 1930; Orostachys thyrsiflora var. rosea (Less.) V. V. Byalt, Novosti Sist. Vyssh. Rast. 32: 46, 2000.

Cotyledon spinosa C. B. Clarke, Fl. Brit. India 2: 416, 1876.

Distribution: China, Mongolia, Russia (Siberia) (Fu et al., 2001).

Key to Spinella and related genera

1. basal leaves not in a conspicuous rosette ································································· Hylotelephium
1. basal leaves in a somewhat conspicuous rosette.
- 2. Leaf apex without spinose appendages ···· Orostachys
- 2. Leaf apex with spinose appendages.
  - 3. Plants biennial; Inflorescences racemose or paniculate··················································· Spinella
  - 3. Plants perennial; Inflorescences cymose ······················································ Meterostachys

Notes

ACKNOWLEDGMENTS

We appreciate the two anonymous reviewers for their helpful comments and suggestions on an early draft of this paper. This research was supported by a National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT) (RS-2024-00339372) and by the Regional Innovation System & Education (RISE) program through the National Research Foundation of Korea (NRF) funded by the Korean Ministry of Education (MOE) (2025-RISE-10-005).

CONFLICTS OF INTEREST

The authors declare that there are no conflicts of interest.

References

An S.-M., Kim B.-Y., Kang H., Lee H.-R., Lee Y.-B., Park Y.-J., Cheon K.-S., Kim K.-A.. 2023;The complete chloroplast genome sequences of six Hylotelephium species: Comparative genomic analysis and phylogenetic relationships. PLoS ONE 18:e0292056.

Bentham G., Hooker J. D.. 1865. Genera Plantarum 1Reeve & Co. London: p. 1040.

Berger A.. 1930. Crassulaceae. Die Natürlichen Pflanzenfamilien 2nd edth ed. 18aIn : Engler A., Prantl K., eds. Engelmann. Leipzig: p. 343–483.

Borissova A G. 1939. Crassulaceae. Flora of the USSR 9In : Komarov V. L., ed. Izdatel’stvo Akademii Nauk SSSR. Moscow & Leningrad: p. 461–489.

de Candolle A. P.. 1828. Prodromus Systematis Naturalis Regni Vegetabilis 3Treuttel & Würtz. Paris: p. 1–494.

Fischer F. E. L.. 1809;Decas quinta plantarum rariorum. Mémoires de la Société Impériale des Naturalistes de Moscou 2:274.

Fu K. T.. 1988;Kungia, a new genus of Crassulaceae from China. Acta Phytotaxonomica Sinica 26:155–158.

Fu K., Ohba H., Gilbert M. G.. 2001. Crassulaceae. Flora of China 8In : Wu Z. Y., Raven P. H., eds. Science Press, Beijing and Missouri Botanical Garden Press. St. Louis: p. 202–268.

Gontcharova S. B., Artyukova E. V., Gontcharov A. A.. 2006;Phylogenetic relationships among members of the subfamily Sedoideae (Crassulaceae) inferred from the ITS region sequences of nuclear rDNA. Russian Journal of Genetics 42:654–661.

Gontcharova S. B., Gontcharov A. A.. 2009;Molecular phylogeny and systematics of flowering plants of the family Crassulaceae DC. Molecular Biology 43:794–803.

Kim I. S., Lee Y. N.. 1996;Chromosome studies of Korean Orostachys species (Crassulaceae). Korean Journal of Plant Taxonomy 26:183–190.

Lee H.-R., Kim K.-A., Kim B.-Y., Park Y.-J., Lee Y.-B., Cheon K.-S.. 2022;The complete chloroplast genome sequences of eight Orostachys species: Comparative analysis and assessment of phylogenetic relationships. PLoS ONE 17:e0277486.

Lee H.-R., Kang H., Park Y.-J., Kwak H.-K., Kim H., Park J., Choi H. J., Kim K.-A., Cheon K.-S.. 2025;Phylogenomic study of Orostachys using Angiosperms353: Polyphyly of subsections with taxonomic consequences. Frontiers in Plant Science 16:1696546.

Lee Y. N., Lee K. A.. 2000;Orostachys in Korea. Bulletin of Korea Plant Research 1:31–47.

Mayuzumi S., Ohba H.. 2004;The phylogenetic position of Eastern Asian Sedoideae (Crassulaceae) inferred from chloroplast and nuclear DNA sequences. Systematic Botany 29:587–598.

Messerschmid T. F. E., Klein J. T., Kadereit G., Kadereit J. W.. 2020;Linnaeus’s folly: Phylogeny, evolution and classification of Sedum (Crassulaceae) and Crassulaceae subfamily Sempervivoideae. Taxon 69:892–926.

Ohba H.. 1978;Genetic and infragenetic classification of the Old World Sedoideae (Crassulaceae). Journal of the Faculty of Science, University of Tokyo, Section III 12:139–198.

Ohba H.. 2003. Orostachys. Illustrated Handbook of Succulent Plant: Crassulaceae In : Eggli U., ed. Springer-Verlag. Heidelberg: p. 186–190.

Steudel E. G.. 1821. Nomenclator botanicus, seu synonymia plantarum universalis 1In : Cotta J. G., ed. Stuttgart & Tübingen..

Turland N. J., Wiersema J. H., Barrie F. R., Greuter W., Hawksworth D. L., Herendeen P. S., Knapp S., Kusber W.-H., Li D.-Z., Marhold K., May T. W., McNeill J., Monro A. M., Prado J., Price M. J., Smith G. F.. 2018. International Code of Nomenclature for Algae, Fungi, and Plants (Shenzhen Code) Adopted by the Nineteenth International Botanical Congress Shenzhen, China, July 2017. Regnum Vegetabile 159 Koeltz Botanical Books. Glashütten:

Webb D. A.. 1964. Crassulaceae. Flora Europaea 1In : Tutin T. G., Heywood V. H., Burges N. A., Moore D. M., Valentine D. H., Walters S. M., Webb D. A., eds. Cambridge University Press. Cambridge: p. 350–364.

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