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(3027–3028) Proposals to conserve the names Polypodium asperum ( Cyathea aspera ) and C. muricata ( Cyatheaceae ) with conserved types

2024; Wiley; Volume: 73; Issue: 3 Linguagem: Inglês

10.1002/tax.13188

1996-8175

Michel Boudrie, Georges Cremers, Marcus Lehnert,

Plant Diversity and Evolution

(3027) Polypodium asperum L., Sp. Pl.: 1093. 1 Mai 1753, nom. cons. prop. Typus: Haiti, Departement Sud, Massif de la Hotte, western group, Camp Perrin, N slope of M. Vandervelde, Jardin Coutard, [ca. 18.36°N, 73.91°W], ca. 800 m, 12 Dec 1925, Ekman H5215 (US No. 1710124 [barcode 00801008]; isotypi: F barcode C0677598F, S No. S16-36272, US No. 1303054 [barcode 00801007]), typ. cons. prop. Linnaeus in Species plantarum often referenced names with several sources, but in the case of Polypodium asperum L. (Linnaeus, Sp. Pl.: 1093. 1753), Petiver (Pterigraph. Amer.: 1 [no. 47], t. 4, fig. 7. 1712) is the only reference cited. Proctor (Ferns Jamaica: 143. 1985) lectotypified the name with the illustration in Petiver (l.c.) because no specimen could be found at that time or to this day. Unlike Plumier (Traité Foug. Amér. 1705), Petiver (l.c.) gave no exact information about the origin of the illustrated plant, except for the rather vague enumeration of Caribbean islands in the title, i.e., "Insulis nostris Charibbaeis Viz. Antego, Barbados, St. Christophers, Nevis, Jamaica, etc.", meaning all Caribbean islands that were under British control at that time. However, due to the similarity between the illustrations and short phrases describing the plants in Plumier's and Petiver's works it is generally assumed that Petiver bolstered the variety of ferns displayed in his plates by copying Plumier's illustrations in reduced size and quality, in this case that in Plumier (l.c.: 4–5, t. 3) (Proctor, l.c.; Cremers & al. in J. Bot. Soc. Bot. France 103: 2–117. 2022). Concerning the provenance of the illustrated fern, Hispaniola and Guadeloupe are the only two places in the Caribbean where Plumier ever collected plants (Cremers & al. in J. Bot. Soc. Bot. France 75: 81–110. 2016), and the lectotype location given by Proctor (l.c.) and repeated by Christenhusz (in Bot. J. Linn. Soc. 161: 236. 2009) was actually taken from Plumier (l.c.: 5): "Isle Saint Domingue [= Haiti], en venant de la bande du Sud, à Leogane par le grand Cul-de-Sac". Neither the illustration by Plumier (l.c.: t. 3) nor that by Petiver (l.c.) is sufficient to reliably assign the name Cyathea aspera (≡ Polypodium asperum) to any living tree fern. Plumier (l.c.: 4–5) gives details of the appearance, size and many structures of the plants in his text, but does not mention any scaly indument, which is crucial for tree fern taxonomy. The density of aculei on the leaf axes shown is something that is not observed in nature, at least not in the plants commonly identified as C. aspera (Barrington in Contr. Gray Herb. 208: 39. 1978, as Trichipteris aspera (L.) R.M. Tryon; Proctor, l.c.), the morphological concept of which is based mainly on the illustration of a Jamaican plant given by Hooker & Greville (Icon. Fil. 2: t. 213–215. 1831). Among Caribbean Cyatheaceae, only C. parvula (Jenman) Domin and C. microdonta (Desv.) Domin may come close to the spikiness illustrated by Plumier (l.c.), and actually C. parvula would in this respect be a much better match for the illustrated plant. In order to secure the application of the name C. aspera for the species that is currently recognized under this name, Cremers & al. (l.c. 2022: 62) chose an epitype: "Habitat in Antillis (in P. Rico), Herb. N.-A. Desvaux s.n. (P! [P01518834])". Unfortunately, closer review of this specimen revealed that it represents another species, Cyathea pungens (Willd.) Domin (M. Lehnert, pers. obs.). Just like the lectotype, the epitype lacks any petiole material that could show the distinctive differences between C. aspera with concolorous brown petiole scales and C. pungens with white margined petiole scales. However, the same color differences are repeated in the small scaly indument of the lamina, and the epitype clearly has the characteristics of C. pungens. Moreover, the epitype is from Puerto Rico, from where C. aspera is currently not known (Lehnert & Kessler, unpub. data) and which is not included in the selection of probable provenances cited above. Maintaining this epitypification would necessitate changing the name of two widespread Neotropical species, which is undesirable: (1) Cyathea pungens, which is present in 12 countries, appears in several recent checklists and floral treatments under this name and has 1371 entries (1767 including synonyms) on Pteridoportal (www.pteridoportal.org; accessed 19 Apr 2024) alone, would have to be renamed C. aspera because that name has priority. (2) The specimens hitherto identified as Cyathea aspera, of which there are 702 on Pteridoportal (including synonyms) and 1142 on GBIF (www.gbif.org; accessed 19 Apr 2024), would have to be relabeled with a name from its synonymy. However, this species represents a species complex and is currently under revision (Lehnert & Kessler, unpub. data). The synonym next in line, C. muricata Willd., is here considered a separate species (Lehnert & Kessler, unpub. data). Within its range, the rather common C. aspera would change its name to either C. muricata or C. nitidula Domin, while still co-occurring with a rarer C. aspera, i.e., the former C. pungens. (3) The replacement name for Cyathea aspera in the strict sense after revision would be C. nitidula Domin, a nom. nov. for C. nitens Mart. which is fraught with additional taxonomical complications because it lacks a physical specimen but has three illustrations cited as syntypes, based on plants from three different locations. For the sake of nomenclatural stability, we here propose the conservation of Cyathea aspera with a conserved type from within the likely range of the assumed locus classicus (Plumier, l.c.; Proctor, l.c.; Christenhusz, l.c.), thus rejecting the former epitype (Art. 9 Note 8 of the ICN, Turland & al. in Regnum Veg. 159. 2018). Our choice is missing the important petiole, but it is a historical collection by Ekman, well distributed across herbaria, and shows the most critical character, the laminar scales, which are clearly visible in most of the digital images available online. (3028) Cyathea muricata Willd., Sp. Pl. 5(1): 497. 25–27 Jun 1810, nom. cons. prop. Typus: Martinique, 1900, Duss 4600 (US No. 523952 [barcode 01450400] [image!]; isotypi: F barcode C0677738F [image!]; MO barcode MO-2386164 [image!]), typ. cons. prop. In his protologue, Willdenow (Sp. Pl. 5(1): 497. 1810) cited polynomials from both Plumier (Traité Foug. Amér.: 5–6, t. 4. 1705) and Petiver (Pterigraph. Amer.: 1 [no. 48], t. 4, fig. 8. 1712) as: "Filix arborescens humilis et spinosa. Plum. fil. 5, t. 4." and "Filix arborescens humilis et spinosa. Petiv. fil. 48, t. 4, f. 8" plus "Habitat in Martinica." Proctor (in Howard, Fl. Lesser Antilles 2: 105. 1977) designated Plumier's (l.c.) plate 4 as the lectotype of Cyathea muricata, and later treated the name as synonymous with C. aspera (L.) Sw. (Proctor, Ferns Jamaica: 143. 1985). This synonymy agrees with the earlier revision by Barrington (in Contr. Gray Herb. 208: 39. 1978; as Trichipteris aspera (Sw.) R.M. Tryon). During our work on Plumier's plates (Cremers & al. in J. Bot. Soc. Bot. France 103: 2–117. 2022), we found at P a specimen from herb. Vaillant (P [P02141207]!) labeled with Plumier's polynomial of t. 4 ("Filix arborescens, humilis et spinosa") in Vaillant's handwriting, but also with a small label "Cyathea muricata W" in Desvaux's handwriting. Since it was the oldest specimen and most likely contemporary with the original publication it was chosen as the epitype of C. muricata to fix the application of the name (Cremers & al., l.c.: 39). Unfortunately, a careful examination of this specimen afterwards (M. Lehnert, pers.obs.) has shown that the plant on the sheet is not a Cyathea but Hypolepis repens (L.) C. Presl (Dennstaedtiaceae). The frond has inconspicuous sori, typical of Hypolepis, i.e., being marginal and hidden under a revolute marginal lobe acting as indusium. This would have grave taxonomic consequences in the sense that, according to the epitypification, C. muricata should become a synonym of H. repens. This inadvertent name transfer would be taxonomically without relevance as long as C. muricata is regarded as synonymous with C. aspera; however, recent revision of this species complex favors the recognition of C. muricata as a separate species (Lehnert & Kessler, unpub. data). The choice of the Vaillant specimen also means that the designated epitype is taxonomically in conflict with Willdenow's (l.c.) description and protologue. To correct this situation, and in agreement with Art. 9.20 of the ICN, we propose to conserve Cyathea muricata with a different conserved type, a specimen with verified origin from the type locality, thus rejecting the earlier epitype (Art. 9 Note 8), in order to conserve the application of the name to the species currently understood as C. muricata. Our choice of Duss 4600 is of a widely distributed collection, with three sheets in United States herbaria documented so far. Although no duplicate was found at P, there is a high probability that further isotypes will be discovered in other herbaria.