J. Biodivers. Conservation 10(2): 187-189
2026
ISSN: 2457-0761 (online)
Rajeev Kumar Singh
Botanical Survey of India, Arid Zone Regional Centre, AIIMS Road, Jodhpur – 342014, Rajasthan, India
E-mail: rksbsiadsingh@gmail.com; ORCID: https://orcid.org/0000-0002-0136-9243
DOI: https://doi.org/10.5281/zenodo.20711008
Article Details: Received: 2026-01-24 | Accepted: 2026-06-10 | Available online: 2026-06-16
Licensed under a Creative Commons Attribution 4.0 International License
Abstract: The morphological characters described in the protologue of Cynanchum cuspidatum Hook. & Arn. (≡ Cynanchum hookerianum Steud.) support its placement in the genus Metastelma R.Br. Accordingly, a new combination is proposed.
Keywords: Brazil, Cynanchum cuspidatum, Cynanchum hookerianum, Lectotype, Metastelma cuspidatum
Introduction
Metastelma R.Br. comprises about 94 species, distributed in tropical and subtropical America (POWO, 2026). In Brazil, the genus is represented by seven species, namely M. ditassoides Schltr., M. giuliettianum Fontella, M. harleyi Fontella, M. hirtellum (Oliv.) Liede, M. hookerianum (Steud.) R.Kr.Singh, M. myrtifolium Decne. and M. parviflorum (Sw.) R.Br. ex Schult. (POWO, 2026). Except M. hirtellum and M. parviflorum, all other are endemic to Brazil. The vegetative and floral characters of Cynanchum cuspidatum Hook. & Arn. (≡ Cynanchum hookerianum Steud.), as presented in the protologue, correspond to those of Metastelma R.Br. Therefore, a new combination is proposed herewith. In addition, lectotype is designated here for the name Cynanchum hookerianum Steud. in accordance with the guidelines and recommendations of Article 9 of the International Code of Nomenclature for algae, fungi, and plants (Turland et al., 2025).
New combination
Metastelma hookerianum (Steud.) R.Kr.Singh, comb. nov.
≡ Cynanchum cuspidatum Hook. & Arn., J. Bot. [Hooker] 1: 293. 1835, nom. illeg., non Thunb., Observ. Cynanch. 6. 1821. Cynanchum hookerianum Steud., Nomencl. Bot. [Steudel], ed. 2, 1: 462. 1841.
Metastelma cuspidatum (Hook. & Arn.) Decne., Prodr. [A.P. de Candolle] 8: 516. 1844, nom. illeg. et superfl.
Figure 1: Lectotype of Cynanchum hookerianum Steud. (K000096344, © The Trustees of the Royal Botanic Gardens, Kew)
Lectotype (designated here or perhaps holotype): Brazil, South Brazil, Woods of Lagoa, s.d., Tweedie 221 (K000096344!, Figure 1).
Distribution: Bra zil (South Brazil).
Acknowledgements
The author is grateful to the Director, Botanical Survey of India, Kolkata and the Head of Office, Botanical Survey of India, Arid Zone Regional Centre, Jodhpur for providing the facilities. The author also thanks the Curator of K for making the image of the type specimen available online.
References
POWO. (2026). Plants of the World Online. Royal Botanic Gardens, Kew. Available from: http://www.plantsoftheworldonline.org/ (accessed 15 January 2026).
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. and Smith, G.F. (2018). International Code of Nomenclature for algae, fungi, and plants (Shenzhen Code). Regnum Vegetabile 159. Koeltz Botanical Books, Glashütten. https://doi.org/10.12705/Code.2018
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