(3127) Proposal to reject the name <i>Ficus calyculata</i> ( <i>Moraceae</i> )

(3127) Ficus calyculata Mill., Gard. Dict., ed. 8: Ficus No. 11. 16 Apr 1768 [Angiosp.: Mor.], nom. utique rej. prop. Typus: non designatus. Philip Miller (Gard. Dict., ed. 8: Ficus No. 11. 1768) described Ficus calyculata based on material collected by William Houstoun. The protologue includes the descriptions: “Ficus foliis ovatis integerrimis obtusis, oppositis, fructu globoso, calyculato” and “Ficus folio lato subrotundo, fructu globoso, magnitudine nuces moschatae”. The latter corresponds to Houstoun's polynomial for F. calyculata, listed on page 120 of his Manuscript Notes, where he recorded “V.C.” (an abbreviation for Veracruz) as the locality of origin, representing the first fig species described from Mexico and one of the earliest described from the Neotropics. Houstoun's original manuscript, now housed in the Natural History Museum's library collection, was in Miller's possession since early 1730 but was later annotated by other curators. For example, the word “Spec.” appears in black ink in the hand of Jonas C. Dryander, one of the curators of Joseph Banks's herbarium, into which Miller's herbarium was incorporated in 1774. This suggests that a corresponding specimen collected by Houstoun was once part of Miller's original collection. Additionally, the name F. calyculata bears a pencil tick in Joseph Banks's copy of the 8th edition of the Gardeners dictionary, which reflects a practice by Daniel C. Solander and Jonas C. Dryander (curators of Banks's herbarium at that time) to mark species present in Miller's collection after its acquisition by Banks. During an exhaustive search of the entire collection of Neotropical Ficus in the General Herbarium and in the Sloane Herbarium at the Natural History Museum in London, the second author was able to trace only a single fig specimen collected by W. Houstoun in Veracruz (i.e., BM barcode BM015177260). However, this specimen does not match Miller's original description of F. calyculata. For example, it has distinctly long petioles, whereas Miller described the leaves of F. calyculata as nearly sessile; moreover, the specimen lacks fruits with a persistent involucre, which we interpret as Miller's intended meaning when referring to a “calyx”. Moreover, this specimen is filed under F. citrifolia Mill. (l.c.: Ficus No. 10), as currently circumscribed, and was initially referred by Daniel C. Solander to F. maxima Mill., though he later reassigned it to his own unpublished manuscript name “Ficus pedunculata”. A much later pencil annotation on the verso of the sheet (likely in the hand of William Fawcett or Charles D. Adams) suggests that the specimen may have actually been collected by Houstoun in Jamaica, as it closely resembles Houstoun's material in Herb. Sloane in H.S. 7 fol. 79a (i.e., BM barcode BM000594120). However, the original specimen described by Miller as F. calyculata remains unlocated and is now presumed to be lost, as previously suggested by Standley (in Contr. U. S. Natl. Herb. 20: 33. 1917) and Ibarra-Manríquez & al. (in Bot. Sci. 90: 412. 2012). Attempts to clarify the taxonomic identity of Ficus calyculata Mill. have thus far proven inconclusive, due in part to its vague diagnosis. In his treatment of Mexican and Central American species of Ficus, Standley (l.c.) listed F. calyculata under “doubtful and excluded names”, although he tentatively proposed possible affinities with F. cookii Standl. (l.c.: 15) or F. cotinifolia Kunth (in Humboldt & al., Nov. Gen. Sp. 2, ed. qu.: 49; ed. fol.: 39. 1817). The structure referred to by Miller as a “calyx”, however, has led several earlier authors to speculate on its potential synonymy with the current concept of the F. aurea complex, as defined by the late C.C. Berg (in Experientia 45: 609. 1989; in Blumea 52: 302. 2007), and based on F. aurea Nutt. (N. Amer. Sylv. 2: 4. 1846), a species distributed across North America (U.S.A. [Florida] and Mexico), Central America, and the Antilles. This complex comprises ca. 15 taxa characterized by the presence of two large basal bracts protecting the fig and a prominent, variably shaped base that supports the receptacle. Some authors recognize F. aurea as the only accepted species in the complex (e.g., Ibarra-Manríquez & al., l.c.), while others recognize up to five (e.g., Hernández-Esquivel & al. in J. Syst. Evol. 58: 263–281. 2020). The name F. aurea, the most widely accepted taxon and the one most closely aligned with Miller's concept of F. calyculata, has already been proposed for conservation by Berg (in Taxon 52: 369. 2003) against F. ciliolosa Link (Enum. Hort. Berol. Alt. 2: 450. 1822). However, he overlooked F. calyculata as a potential older epithet, likely because he was simultaneously reappraising F. aurea as a later synonym of F. maxima Mill. (l.c.: Ficus No. 6), the latter ultimately successfully proposed for conservation under a conserved type. With no extant type material for F. calyculata, he was unable to reconcile it with F. aurea. Outside the Ficus aurea complex, F. calyculata has only been accepted as a valid species by Carvajal & al. (in Fl. Bajío Reg. Adyacent. 147: 15. 2007) and was subsequently designated as the type for F. subser. Calyculatae Carvajal (in Ibugana 3: 46. 2012). This subseries includes F. calyculata and F. cookii, which are distinguished solely by the sessile nature of the figs in F. calyculata. However, this taxonomic proposal lacks supporting typification or morphological evidence. Carvajal (l.c.) also acknowledged that geographic overlap between the two could complicate their taxonomic separation. Notably, no modern taxonomic treatment of Neotropical Ficus, including Berg (l.c. 2007), regional monographs (Ibarra-Manríquez & al., l.c.; Berg in Davidse & al., Fl. Mesoamer. 2: 90–116. 2012; Ulloa-Ulloa & al. in Science 358: 1614–1617. 2017), or detailed studies of the F. aurea complex (Hernández-Esquivel & al., l.c.) has adopted Carvajal's classification or recognized F. calyculata as a valid species. Despite the unresolved identity of F. calyculata, some global online databases (e.g., World Flora Online, accessed 7 Sep 2025; Plants of the World Online, accessed 7 Sep 2025) continue to list it as an accepted species. Although Miller's concept of Ficus calyculata could arguably refer to F. aurea and might represent the earliest name applicable to that taxon, the absence of original material precludes its definitive identification. Furthermore, “calyculate” figs occur in multiple species across the F. aurea complex, thereby compounding the ambiguity. Consequently, any attempt to fix the application of the name through arbitrary neotypification using material from within the F. aurea complex would only introduce further nomenclatural confusion. Adopting F. calyculata as the correct name for any taxon within the F. aurea complex would constitute an undesirable and disruptive nomenclatural change. The most effective way to safeguard nomenclatural stability is to reject the name Ficus calyculata outright under Art. 56 of the Madrid ICN (Turland & al. in Regnum Veg. 162. 2025). Given the minimal usage of F. calyculata in the scientific literature [30 results on Google Scholar, accessed on 7 Sep 2025] relative to the widespread and consistent application of F. aurea [1430] or other names within the complex (e.g., F. cookii [77], F. isophlebia [41], F. tecolutensis [193], F. tuerckheimii [135]), we strongly advocate that the proposal to reject the name F. calyculata be adopted. Acceptance of this proposal would permanently eliminate any threat posed by F. calyculata to F. aurea, or to any other name subsequently recognized as accepted within the F. aurea complex. Conversely, failure to reject the name would leave open the possibility of its future resurrection, potentially displacing a well-established and widely adopted name as a later synonym of F. calyculata.