(3119) Proposal to reject the name <i>Bryonia pinnatiloba</i> (<i>Cucurbitaceae</i>)

(3119) Bryonia pinnatiloba M. Roem., Fam. Nat. Syn. Monogr. 2: 40. Dec 1846 [Angiosp.: Cucurbit.], nom. utique rej. prop. Lectotypus (hic designatus): [icon in] Vellozo, Fl. Flumin. Icon. 10: t. 90. 29 Oct 1831. The name Bryonia pinnatiloba was published by Roemer (Fam. Nat. Syn. Monogr. 2: 40. 1846), based on the illustration of “Bryonia pinnatifida” (Vellozo, Fl. Flumin. Icon. 10: t. 90. 1831 [“1827”]), which was issued without analysis or accompanying text. Although Vellozo's plate was used by Roemer, the plate lacks sufficient diagnostic characteristics to allow unequivocal identification of the species, such as reproductive structures or the trichomes, which could serve as analysis, as required by Art. 38.1 and 38.9 of the International Code of Nomenclature (Turland & al. in Regnum Veg. 162. 2025). Therefore, “B. pinnatifida Vell.” cannot be considered validly published in 1831. Furthermore, even if so published, it would have been a later homonym of B. pinnatifida Burch. (Trav. S. Africa 1: 547. 1822). Other authors have also attempted to name the species illustrated by Vellozo. Steudel (Nomencl. Bot., ed. 2, 1: 233. 1840) published “Bryonia subpinnata”, citing Vellozo's “B. pinnatifida. Arrab. (non Burch.)” as a synonym. Considering that Vellozo's designation was not validly published, “B. subpinnata” is also not a validly published name and has no nomenclatural standing. On the other hand, Roemer (l.c.) provided both a diagnosis and description for B. pinnatiloba, based on the published plate in Vellozo (l.c.), thus meeting the requirements of Art. 38.1 for valid publication under the Code. Taxonomically, “Bryonia pinnatifida” (Vellozo, l.c.) and B. pinnatiloba are considered conspecific with Cayaponia diversifolia (Cogn.) Cogn. (in Candolle & Candolle, Monogr. Phan. 3: 787. 1881), which is based on Trianosperma diversifolium Cogn. (in Martius & al., Fl. Bras. 6(4): 92. 1878, ‘diversifolia’) (Gomes-Klein & al. in Flora e Funga do Brasil. 2025, accessed 22 Jul 2025). Thus, B. pinnatiloba (for which a combination in Cayaponia is available) would represent the oldest name for the species currently treated as C. diversifolia. However, this nomenclatural change would be disruptive. Cayaponia diversifolia has been widely accepted and used for over a century in specialized literature and taxonomic monographs (e.g., Gomes-Klein, Estud. Tax. Cayaponia Brasil. [Ph.D. Thesis, Univ. São Paulo]. 2001; Cardoso Junior, Cayaponia Estad. Goiás: Abord. Morfol. Anatôm. [Master's Diss., Univ. Federal de Goiás]. 2017) and major floristic and taxonomic databases in Brazil and South America (e.g., Flora e Funga do Brasil; Flora del Conosur; both accessed 19 Jul 2025). Moreover, the absence of a type specimen and the exclusive reliance on a poorly diagnostic illustration introduce taxonomic ambiguity, which may hinder the accurate application of the name (cf. Pastore in Phytotaxa 108: 41–48. 2013; Knapp & al. in Taxon 64: 822–836. 2015). Nevertheless, the published illustration in Vellozo (l.c.: t. 90) is here designated as lectotype of B. pinnatiloba, as it was the only original material (Art. 9.4) available to Roemer and is the only element available for lectotypification (Art. 9.12). For these reasons, and in accordance with Art. 56.1, we propose the formal rejection of the name Bryonia pinnatiloba M. Roem., to preserve nomenclatural stability and ensure the continued use of the well-established and widely recognized name Cayaponia diversifolia. This paper is part of the Ph.D. thesis by HFM at the Programa de Pós-Graduação em Biologia de Fungos, Algas e Plantas of Universidade Federal de Santa Catarina. HFM is grateful for the financial support from CAPES via a doctoral scholarship grant (88887.821398/2023-00). JP and JFBP thank the Conselho Nacional de Desenvolvimento Científico e Tecnológico-CNPq (Proc. n. 307931/2021-8, 304082/2023-6, respectively) for the financial support.