(3080) Proposal to conserve the name <i>Acalypha ostryifolia</i> against <i>A. persimilis</i> (<i>Euphorbiaceae</i>)

(3080) Acalypha ostryifolia Riddell ex J.M. Coult. in Mem. Torrey Bot. Club 5: 213. 14 Jun 1894, nom. cons. prop. Neotypus (hic designatus): [U.S.A., Ohio], Cincinnati, Lea 19 (NY barcode 00232985). (=) Acalypha persimilis Müll. Arg. in Linnaea 34: 25. Mar 1865, nom rej. prop. Lectotypus (hic designatus): [Cuba?], Sessé & Mociño?, ex Herb. Pavón (G barcode G00383598). The name Acalypha ostryifolia was first proposed (as “ostryafolia”) by Riddell (Syn. Fl. West. States: 33. 1835), who wrote that it had been collected by T.G. Lea, “on one of the Kentucky hills opposite Cincinnati. Aug.–Sept.” Riddell suggested that his species was “probably” A. caroliniana sensu Elliott (Sketch Bot. S. Carolina 2: 645. 1824), not Walter (Fl. Carol.: 238. 1788, now a synonym of A. virginica L.), and provided a very brief description: “The leaves resemble in form, those of Ostrya virginica”; he also indicated that the plant might be an annual. Although it was clear that the name A. caroliniana had been applied differently by Walter and Elliott, authors throughout most of the nineteenth century, for example Gray (Manual, ed. 2: 390. 1856) and Müller (in Candolle, Prodr. 15(2): 842–843. 1866), continued to use that name, listing A. ostryifolia as a synonym. It was not until late in the century that Riddell's name became widely accepted, initially by Coulter (in Mem. Torrey Bot. Club 5: 213. 1894) and Britton & Brown (Ill. Fl. N. U.S. 2: 365. 1897). Riddell's name has been used for this species almost continuously since that time, the only notable exception being by Pax & Hoffmann (in Engler, Pflanzenr. IV. 147 XVI (Heft 85): 43. 1924), who continued to use A. caroliniana. However, recently Riddell's publication of A. ostryifolia has been considered to be invalid because the scanty description can be interpreted simply as the name's etymology and his uncertain reference to Elliott precludes validation through that description (https://www.ipni.org/n/337658-1; K. Gandhi, pers. comm.). On that basis, it appears that the earliest validation of the name was by J.M. Coulter (l.c.), who definitely associated A. ostryifolia with Elliott's description of A. caroliniana. Riddell (l.c.) did not indicate the herbarium where Lea's material was located or cite a collection number. We have found collections of Acalypha ostryifolia made by Lea at DWC (barcode 3172700724300), NY (barcode 00232985), and PH (barcodes PH00692434 and PH00692435). All bear labels in the same hand, and, as noted by Steinmann & Felger (in Aliso 16: 14. 1997), the label on the NY specimen also says “Doct. Riddell has made a mistake in its station. I have found it only as a garden weed”, thus associating the handwriting with Lea himself. Various numbers, which might be collection numbers, appear on the specimens: 19 (NY and PH barcode PH00692435), 19-15 (PH barcode PH00692434), and 168 (DWC). Only the NY specimen has locality information, given as “a garden weed | Cincinn”, although the DWC specimen is labelled “found as a garden weed only”, and “T. G. Lea | garden”, and the PH specimens state either “in the garden, an annual weed” (barcode PH00692435) or “cultivated ground” (barcode PH00692434). Two of the specimens (DWC and NY) are dated only as “Sep.” and PH barcode PH00692434 is dated “Aug. 9”, but the only specimen to bear a complete date, PH barcode PH00692435, has “Sep 12/38” or “Sep/2/38” at the end of a long description; this date, which could be either a collection date or the date of the label with description, is more than three years after Riddell published his description of A. ostryifolia. All four specimens are determined as “Acalypha ostryafolia Ridd.!” in Lea's hand, and two also reference Riddell's publication, as either “Synop. 33” (NY) or “Syn: p. 33” (PH barcode PH00692435), again in Lea's hand. Nothing about the ink or spacing on the labels indicates that the determination was added after the rest of the label was written. Thus, the label information suggests that the labels, and perhaps the collections themselves, were all made after Riddell's publication. Because we cannot be sure that any of these specimens represent original material, it is more appropriate to designate a neotype than a lectotype. We choose the NY specimen because it is the only one with a locality. It is possible that the PH specimen numbered 19 (barcode PH00692435) is an isoneotype. The name Acalypha persimilis was proposed by Müller-Argoviensis (in Linnaea 34: 25. 1865); in the protologue, Müller stated “In Cuba (hb. Pavon! in hb. Boiss., etiam in hb. Berol. ex. hb. Franqueville).” The specimen cited at B is no longer in the herbarium and presumably was destroyed during the bombing of Berlin in the Second World War. Thus, the only extant original material is the specimen at G (barcode G00383598) from Boissier's herbarium. This specimen bears a label “Nueva España, Herb. Pavon.” José Antonio Pavón never collected in Mexico or the West Indies where A. persimilis is known (McVaugh in Contr. Univ. Michigan Herb. 16: 155–171. 1987), but he extracted specimens from the herbarium of the Martín de Sessé y Lacasta and José Mariano Mociño expedition to the Virreinato de Nueva España from 1787 to 1803 and sold them to various botanists. Some of the material Pavón sent to Aylmer Bourke Lambert eventually came to G by way of the Boissiers (McVaugh, l.c. 1987), and this specimen likely was among them. Why Müller reported the specimen from Cuba is unknown, but possibly the locality information was provided on the destroyed sheet reported from B. Sessé spent almost a year collecting in Cuba in 1795 (McVaugh in Contr. Univ. Michigan Herb. 11: 97–195. 1973), so it is possible the collection is from there rather than Mexico, where the expedition spent most of its time (McVaugh, l.c. 1973). We designate the specimen at G as the lectotype. As its specific epithet indicates, Müller considered Acalypha persimilis very similar to some other species, specifically A. ostryifolia (as A. caroliniana sensu Elliott) and A. setosa A. Rich., but he did not state how it differed from them. Because A. setosa consistently has been considered distinct from both A. ostryifolia and A. persimilis, we will not consider it further. The following year, Müller (l.c. 1866) extended the range of A. persimilis to include Mexico and indicated that, compared to A. ostryifolia (as A. caroliniana), the pistillate bracts of A. persimilis are more numerous (25–40 vs. 4–7 per inflorescence) and smaller (2.5–3 mm long vs. 5–7 mm long), and their styles differ (distally 3–4-branched vs. pectinately 6–8-branched). Our own observations show that the pistillate inflorescences of A. ostryifolia typically bear 15–30 bracts, and that the lectotype of A. persimilis has immature pistillate bracts, hence their small size, and only one of its pistillate inflorescences has more bracts than typical of A. ostryifolia. The Mexican specimen Müller (l.c. 1866) cited has pistillate inflorescences with bracts that are similar in number and size to those typically found in A. ostryifolia, and other authors who have recognized A. persimilis, for example Pax & Hoffmann (l.c.: 43–44) and Standley & Steyermark (in Fieldiana, Bot. 24: 40. 1949), have described the bracts as being 4–5 mm long. Furthermore, the differences in stylar morphology noted by Müller (l.c. 1866) are not supported by observations of more specimens (Levin, pers. obs.). Pax & Hoffmann (l.c.: 42) differentiated Acalypha ostryifolia (as A. caroliniana sensu Elliott) from A. persimilis based on the pistillate bracts of the former being stipitate-glandular and those of the latter being eglandular. They also expanded the ranges for both species, stating that A. ostryifolia was known from the eastern United States through Mexico and that A. persimilis was known from the Greater Antilles, Mexico, and Guatemala. We have been unable to find any other publications that considered both species prior to 1953, when Alain (in León & Alain, Fl. Cuba 3: 97. 1953) synonymized the two names without explanation. Although Steinmann & Felger (l.c.: 14–15) did not specifically consider A. persimilis, they noted that the pistillate bracts of A. ostryifolia may be stipitate-glandular or eglandular, with both forms sometimes found at the same locality, thereby suggesting that the two species cannot be differentiated using the single character Pax & Hoffmann (l.c.) used to distinguish them. In 2005, Levin annotated the lectotype of A. persimilis as A. ostryifolia. Cardiel & Muñoz-Rodríguez (in Bot. Complut. 37: 55. 2013), when discussing the taxonomy of A. sect. Sclerolobae Müll. Arg., which contains A. ostryifolia and its close relatives, also regarded A. ostryifolia and A. persimilis as synonyms. This synonymy has always been followed in the few recent floristic treatments that include both names, for example Adams (Flow. Pl. Jamaica: 423. 1972), Liogier (Descr. Fl. Puerto Rico Adj. Isl., Spermatoph. 2: 348. 1988), Acevedo-Rodríguez & Strong (in Smithsonian Contr. Bot. 98: 317. 2012), and Greuter & Rankin-Rodríguez (Spermatoph. Cuba, Prelim. Checkl.: 134. 2017). Because the name Acalypha ostryifolia is now considered validly published in 1894 (Coulter, l.c.), the name A. persimilis has priority and must be used when it and A. ostryifolia are considered synonyms. However, the name A. persimilis is virtually unknown in the taxonomic and floristic literature. Even using a Google Scholar search, we have been unable to locate any recent publications that accept the name A. persimilis other than some online databases. In contrast, A. ostryifolia has a long, stable, and well-established history of use. A Google Scholar search found 532 publications using the name (or its orthographic variant ‘A. ostryaefolia’), including 319 in the last 20 years. Significantly, about half of these are publications that deal with the species’ status as an agriculturally important weed and/or its interaction with insect pests, demonstrating that this species is economically important. Furthermore, there are literally thousands of specimens labeled as A. ostryifolia in herbaria, and very few labeled as A. persimilis. Conserving the name Acalypha ostryifolia over A. persimilis would preserve a well-established name that has been in use for almost two centuries, thus contributing to nomenclatural stability. It would also prevent undesirable changes that could impact taxonomic, floristic, and agronomic studies. Adopting the older, rarely used name would be disruptive. We thank Barney Lipscomb at the Fort Worth Botanic Garden for bibliographic assistance, and John H. Wiersema for helpful suggestions that improved the manuscript.

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