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(2707) Psyllocarpus Mart. & Zucc. in Flora 7(1, Beil.): 130. Mai–Jun 1824 [Rub.], nom. cons. prop. Typus: P. laricoides Mart. & Zucc. (=) Tapanhuacanga Vand., Fl. Lusit. Bras. Spec.: 9. 1788, nom. rej. prop. Typus (vide Smithsonian ING Staff in Index Nom. Gen.: No. 32953. 1971): T. brasiliensis Steud. (Nomencl. Bot., ed. 2, 2: 663. Aug 1841). Joaquim Vellozo de Miranda sent from Brazil to Portugal original materials, which were copied as watercolor drawings and gathered as a bound folio, accounting for 133 plates containing sketches of the species he studied. These drawings were used by Domenico Vandelli as the basis for his descriptions of new Brazilian taxa. In conjunction with one of the engravings published in the Florae Lusitanicae et Brasiliensis specimen, showing mirror images of original drawings by Vellozo de Miranda, Vandelli (Fl. Lusit. Bras. Spec.: 9, t. 1, fig. 5. 1788; figure reprinted by Moraes in Feddes Repert. 130: 21, fig. 1A. 2019) proposed Tapanhuacanga, but named no species nor gave any indication that there was more than one in the genus. This name has been scarcely cited in the literature (Poiret in Lamarck, Encycl. Suppl. 5: 283. 1817; Jussieu in Mém. mus. Hist. Nat. 6: 372. 1820; Steudel, l.c.; Pfeiffer, Nomencl. Bot. 2: 1351. 1874; Post, Lex. Gen. Phan.: 549. 1903; Stellfeld, Tribuna Farm.: 45. 1967; Farr & Zijlstra, Index Nom. Gen. 1996+ [http://botany.si.edu/ing/, accessed: 20 Apr 2019]; Govaerts, World Checkl. Sel. Pl. Fam. 2019 [https://wcsp.science.kew.org/home.do, accessed: 31 Jan 2019]), usually with doubts on its identity by authors. The only binomial in which it was used was proposed without a description or diagnosis, but since Tapanhuacanga brasiliensis Steud. (l.c.) was unique in the genus and established in reference to Vandelli (l.c.), it was then validly published (Art. 38.12 of the ICN, Turland & al. in Regnum Veg. 159. 2018). This binomial has been cited only by Farr & Zijlstra (l.c.) and Govaerts (l.c.), with doubts, more than a century and a half later. Moraes (l.c.: 49), based on the analysis of an original drawing by Vellozo de Miranda (Brazil, Minas Gerais, [icon] [Tab. I] in an autographed letter sent by Vandelli to Joseph Banks [Library of the Natural History Museum, London: location, Botany MSS VAN; barcode 364295]) and its copy ([icon] by Manoel Piolti from original material [drawing and/or specimen] by Vellozo de Miranda [MUHNAC–UL, Biblioteca de Botânica, No. 145]), revisited Vandelli (l.c.) and concluded that T. brasiliensis, for which he designated the engraving in the same work as lectotype (Vandelli, l.c., [icon] t. 1, fig. 5), is Psyllocarpus laricoides Mart. & Zucc. (l.c.), but no objective argumentation was provided to support that conclusion. Therefore, since Tapanhuacanga has priority over Psyllocarpus, he made 12 new combinations and designated T. laricoides (Mart. & Zucc.) P.L.R. Moraes (l.c.), based on P. laricoides, as genus type. This designation would have made the two genera homotypic, since P. laricoides had already been selected as type of Psyllocarpus by Kirkbride (in Smithsonian Contr. Bot. 41: 15. 1979, under P. sect. Psyllocarpus). However, typification of Tapanhuacanga on T. brasiliensis was already established by Smithsonian ING Staff (on Index Nom. Gen. Card No. 32953, published Mar 1971). Whether or not, as Moraes (l.c.) has stated, the fig. 5 of Vandelli, the type of Tapanhuacanga brasiliensis, is conspecific with Psyllocarpus laricoides, remains an open question. Nevertheless, Tapanhuacanga and Psyllocarpus are heterotypic synonyms. The copy by Manoel Piolti (reprinted in Moraes, l.c.: 50, fig. 10A) of the original drawing by Vellozo de Miranda depicts a subshrub with acicular leaves and flowers with lilac to blue corollas, arranged in 1-flowered cymes, allowing for the identification of the genus to which it belongs. As the engraving in Vandelli (l.c.) is a mirror image of part of Vellozo's drawing, it corresponds to some Psyllocarpus species, although only flower, fruit and seeds are depicted. However, we here question the synonymy between T. brasiliensis and P. laricoides. Psyllocarpus laricoides had its circumscription amended over time. It is an endemic species from Minas Gerais and Bahia, based on original material collected by Martius, for which a lectotype was designated by Kirkbride (l.c.: 16): Brazil, Minas Gerais, in sumo Brasiliae monte Itambé, Martius s.n. (lectotype: M barcode M-0189221 left-hand specimen [annotated as holotype by Joseph H. Kirkbride, Jr., 1976]!; presumed isolectotypes: M barcodes M-0189221 center specimen!, M-0189217! & M0189220!). The species as currently circumscribed includes P. ericoides Mart. & Zucc. (l.c.) and P. laricoides var. β densifolia Mart. (Nov. Gen. Sp. Pl. 1: 45. 1824) as synonyms. It also formerly included P. laricoides var. longicornu K. Schum. (in Martius, F1. Bras. 6(6): 33. 1888) in its synonymy (Kirkbride, l.c.: 16), however Carmo & al. (in Kew Bull. 73(52): 1–6. 2018) noted that the type specimens of this variety resembled P. goiasensis J.H. Kirkbr. (l.c.: 17) in their morphology and that this original material was collected in Goiás, not Minas Gerais as stated by Kirkbride (l.c.), so they transferred P. laricoides var. longicornu to the synonymy of P. goiasensis. The result is that Psyllocarpus laricoides can be characterized by its sympodial branching pattern, glabrous hypanthium, presence of a calyx tube, and triangular to linear calyx lobes 1–2 mm long. We could not observe these characters in any of the T. brasiliensis drawings, which depict a plant that seems to present a monopodial branching pattern. The absence of an actual specimen associated with T. brasiliensis and the lack of such critical details, which are beyond what is observable on these drawings, or even the presence of characteristics possibly divergent from those in relevant type specimens prevent an unequivocal assignment of P. laricoides to T. brasiliensis, even considering the former taxon in its broader sense. Even the recently described P. bahiensis J.A.M. Carmo & al. (in Syst. Bot. 43: 582. 2018), which presents a unique set of characters in the genus, also has been identified as P. laricoides, which is most likely to represent a species complex (Carmo & al., in prep.). Additionally, the origin of the material on which T. brasiliensis drawings were based is uncertain, although it was probably collected in the macro-region of the Serra do Espinhaço, for which several areas of endemism have been identified. According to Moraes (l.c.) it could have been collected in several localities around Ouro Preto, in a region known as the “Iron Quadrangle”, or Conceição do Mato Dentro, in the eastern slopes of Serra do Cipó, whereas Martius made his collections of P. laricoides specimens in the region of the Diamantina Plateau, around Santo Antônio do Itambé and Diamantina, all of which fall in different major areas of endemism in the Serra do Espinhaço (Echternacht & al. in Flora 206: 782. 2011). For these reasons we argue that the identity of T. brasiliensis (1841) is still unclear. Although congeneric with P. laricoides, it is not referable to any Psyllocarpus species whose name was published later than 1841, so T. brasiliensis does not threaten any of these names and proposing its rejection under Art. 56 is unnecessary. Since its publication, Psyllocarpus has been consistently used in works, such as floras (e.g., Schumann in Martius, l.c. 1888: 30; Zappi & Stannard in Stannard, Fl. Pico das Almas: 572. 1995; Campos & al. in Bol. Bot. Univ. São Paulo 24: 61. 2006; Delprete in Rizzo, Fl. Est. Goiás Tocantins 40: 979. 2010; Delprete in Cavalcante & Dias, Fl. Distrito Federal 10: 203. 2012; Zappi & al. in Bol. Bot. Univ. São Paulo 32: 130. 2014; Borges & al. in Rodriguésia 68: 614. 2017), illustrated guides (e.g., Souza & Lorenzi, Bot. Sist., ed. 3: 570. 2012; Zappi & al., Pl. Setor Noroeste da Serra do Cipó, Minas Gerais: 167. 2014; Souza & al., Guia das Plantas do Cerrado: 462. 2018), palynological and micromorphological studies (e.g., Dessein & al. in Grana 41: 70. 2002, in Bot. Rev. (Lancaster) 71: 409. 2005; Silveira Júnior & al. in Acta Bot. Brasil. 26: 444. 2012; Salas & Cabral in Bol. Soc. Argent. Bot. 49: 52. 2014; Judkevich & al. in Int. J. Pl. Sci. 178: 382. 2017), phylogenetic/evolutionary studies (e.g., Dessein & al. in Taxon 54: 107. 2005; Kårehed & al. in Molec. Phylogen. Evol. 49: 845. 2008; Groeninckx & al. in Ann. Missouri Bot. Gard. 96: 113. 2009; Guo & al. in Molec. Phylogen. Evol. 67: 111. 2013; Neupane & al. in Taxon 64: 322. 2015, in Amer. J. Bot. 104: 420. 2017), printed checklists (e.g., Giulietti & al. in Bol. Bot. Univ. São Paulo 9: 93. 1987; Andersson, Prov. Checkl. Neotrop. Rubiaceae [Scripta Bot. Belg. 1]: 172. 1992; Zappi & al. in Bol. Bot. Univ. São Paulo 21: 387. 2003; Mourão & Stehmann in Rodriguésia 58: 780. 2007; Borges & al. in Rodriguésia 62: 147. 2011; Teixeira & Lemos Filho in Bol. Bot. Univ. São Paulo 31: 225. 2013), red list of threatened species (e.g., Zappi & al. in Martinelli & al., Livro Vermelho Fl. Brasil, Pl. Raras do Cerrado: 237. 2014), and metal accumulation studies (e.g., Jansen & al. in Ann. Bot. (Oxford) 85: 97. 2000; Schettini & al. in Flora 238: 176. 2018), or in online databases (e.g., Flora do Brasil 2020 [http://floradobrasil.jbrj.gov.br/]; Global Biodiversity Information Facility [http://gbif.org]; JSTOR Global Plants [https://plants.jstor.org/]; speciesLink [http://www.splink.org.br]; Tropicos [https://www.tropicos.org/]; World Checklist of Selected Plant Families [http://wcsp.science.kew.org]). The application of the principle of priority is clearly disruptive in this case, as the long-established and widely used legitimate name Psyllocarpus would have to be abandoned in favor of Tapanhuacanga, a name that has been rarely cited and generally treated with uncertainty. Furthermore, the combinations of all Psyllocarpus names undertaken by Moraes (l.c.) were based purely on nomenclatural reasons, disregarding detailed and critical examination of herbaria material and ongoing research on the Spermacoceae tribe, as we've shown evidence at the VII International Rubiaceae and Gentianales Conference, held in Copenhagen, Denmark, in 2017 (Carmo & al. in VII International Rubiaceae and Gentianales Conference, Copenhagen, Denmark. 2017) that the genus as currently circumscribed is not monophyletic (Carmo & al., in prep.), therefore some of these new combinations will be relegated to synonymy. In summary, to serve stability and avoid disadvantageous changes purely based on nomenclatural reasons (Art. 14.1 of the ICN) we here propose the conservation of Psyllocarpus against Tapanhuacanga. JAMC, https://orcid.org/0000-0002-7660-9918 RMS, https://orcid.org/0000-0001-7799-9017 SVS, https://orcid.org/0000-0001-8463-0429 AOS, https://orcid.org/0000-0001-6555-8759 The first author acknowledges Capes and CNPq for the doctoral fellowship; Capes for the PDSE scholarship (process 88881.135488/2016-01); the Missouri Botanical Garden for the Shirley A. Graham Fellowship in Systematic Botany and Biogeography; Gustavo Shimizu for the comments and suggestions on an earlier version of the manuscript; the Biodiversity Heritage Library (BHL) for providing easy and free access to biodiversity literature and archives; John McNeill for comments and suggestions, and clarifications on the Code; and Fred R. Barrie for information on the typification of Tapanhuacanga.