(118) Proposal to amend Article 41.5 and add an Example clarifying requirements for referring to a basionym or replaced synonym

Abstract

“41.5. On or after 1 January 1953, a new combination, name at new rank, or replacement name is not validly published unless its basionym or replaced synonym is clearly indicated and a full and direct reference given to its author and place of valid publication, with page or plate reference and date (but see Art. 41.6 and 41.8). Valid publication is not achieved by reference to a new combination based on the actual basionym or replaced synonym (but see Art. 41.8), unless that new combination is the illegitimate name being replaced by a replacement name. On or after 1 January 2007, a new combination, name at new rank, or replacement name is not validly published unless its basionym or replaced synonym is cited.” “Ex. 16bis. The intended replacement name “Hemionitis atreyu” was not validly published by Christenhusz (in Christenhusz & al., Global Fl. 4: 10. 2018) because that author made no reference to the replaced synonym, Pteris acrostica Balb. (Elenco: 98. 1801), instead citing “Cheilanthes acrostica Tod., Giorn. Sci. Nat. Econ. Palermo 1: 215. 1866”, which is in fact a new combination, C. acrostica (Balb.) Tod., based on P. acrostica, which Todaro explicitly cited as the basionym.” The proposed amendments to Art. 41 of the Code (Turland & al. in Regnum Veg. 159. 2018) were initiated due to the nomenclatural case of “Hemionitis atreyu” Christenh. proposed as a replacement name (Christenhusz, l.c.). Mosyakin (in Phytotaxa 373: 164–168. 2018) initially considered it not to be a validly published name because Christenhusz did not cite the earliest replaced synonym, Pteris acrostica, and its author and place of valid publication, but cited instead a new combination, Cheilanthes acrostica, based on P. acrostica. Mosyakin (l.c.) also noted that in fact a new combination, H. acrostica (Balb.) Mosyakin (l.c. 2018: 165), not a replacement name, was required. However, in IPNI (https://www.ipni.org; accessed 30 Oct 2018 and 2 Mar 2021) the name Hemionitis atreyu was treated as an illegitimate name: “nom. illeg. nom. superfl., the epithet acrostica was available for use and should have been taken up as H. acrosticha Noronha is a nom. inval. nom. nud.” The following remark was also provided: “Although Christenh. cited a combination and not the earliest homotypic synonym, since it is a replaced synonym (not a basionym) the replacement name is nevertheless validly published” (updated nomenclatural notes made on 2018-10-26 16:25:24.0, by H.L. Lindon, as indicated in IPNI). Indeed, there seems to be no rule in the current Shenzhen Code to preclude a replaced synonym being a new combination. Accordingly, the IPNI interpretation of the situation seems to be correct and therefore Hemionitis atreyu is a validly published but illegitimate name (see a correction by Mosyakin in Phytotaxa 405: 276–277. 2019). If we accept that interpretation, a full and direct reference to any new combination based on the actual replaced synonym (i.e. without a basionym) would be sufficient for valid publication of a replacement name on or after 1 January 1953. Hemionitis atreyu could have been validated by a full and direct reference to any of the new combinations based on Pteris acrostica: Cheilanthes acrostica, Allosorus acrosticus (Balb.) Christenh., Oeosporangium acrosticum (Balb.) L. Sáez & P. Aymerich, etc. (see full synonymy in Mosyakin, l.c. 2018: 165). This interpretation, however, is against what one could presume to be the intent or meaning of Art. 41.5 requiring, for valid publication of a replacement name on or after 1 January 1953, the clear indication of the actual replaced synonym, i.e. either the earliest replaced synonym – but not new combinations based on it (but see Art. 41.8) – or the actual illegitimate name in need of replacement, and a full and direct reference to its author(s) and place of valid publication, by analogy with corresponding requirements for valid publication of a new combination or name at new rank, which requires clear indication of and reference to its basionym, which does not itself have a basionym (see Art. 6.9). It would be only logical to apply the same requirements to new combinations, names at new rank and replacement names. I am grateful to John McNeill (Royal Botanic Garden, Edinburgh, Scotland, U.K. & Royal Ontario Museum, Toronto, Ontario, Canada) and Kanchi N. Gandhi (Harvard University Herbaria and Library, Cambridge, MA, U.S.A.) for their advice on nomenclatural issues and to Nicholas J. Turland (Botanischer Garten und Botanisches Museum Berlin, Freie Universität Berlin, Berlin, Germany) and John H. Wiersema (Smithsonian Institution, Washington, D.C., U.S.A.) for their useful comments on the manuscript and many editorial improvements.